JP2020503790A - Handover method, core network device, access network device, and terminal device - Google Patents

Abstract

A handover method, a core network device, an access network device, and a terminal device are provided. The handover method determines that the second core network device needs to switch a connection between the terminal device and the second core network device to a connection between the terminal device and the first core network device. And wherein the first core network device and the second core network device communicate with the terminal device by using the same access network device, wherein the second core network device sends a change message to the first core network device. The change message, the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. There is a first core network device Used to notify the scan, and a stage. Based on the handover procedure initiated by the second core network device, the connection between the terminal and the second core network can be switched to the connection between the terminal and the first core network without switching the access network device. Can be switched, thereby efficiently fulfilling network communication requirements.

Description

  Embodiments of the present invention relate to the field of wireless communication technology, and more specifically, to a handover method, a core network device, an access network device, and a terminal device.

  In a conventional wireless communication network, there is usually an independent network. Correspondingly, each network has a core network device and an access network device corresponding to the network. FIG. 1 shows two independent networks. A 3G network is used as an example. The core network device of the 3G network may be a serving GPRS support node (SGSN) and the access network device of the 3G network may be a radio network controller (RNC). For a 4G network, the access network device of the 4G network may be an eNB, and the core network device of the 4G network may be a mobility management entity (MME) or a PDN gateway (P-GW) / gateway GPRS support node (GGSN). ). When a terminal device is handed over from one network to another, for example, when a terminal device is handed over from a 3G network to a 4G network, the access network device and the core network device of the two networks need to be scheduled. Specifically, the following procedure or a similar procedure may be included. The RNC determines the target cell that needs to perform the handover based on the UE measurement, selects the target eNB based on the target cell, and sends a handover request to the SGSN. SGSN forwards the handover message to MME. The MME establishes a connection between the S-GW / P-GW and the eNB in the LTE network. After establishing a connection with the target eNB, the MME informs the SGSN of the radio connection bearer (RAB) that has been successfully established, and the SGSN communicates with the failed RAB that needs to be released and the data transfer. Responsible for notifying the RNC of the required, successfully established RAB.

  With the development of wireless communication technology, when the network structure changes, the existing solutions cannot solve the problem of switching the connection between the terminal device and the core network device.

  Embodiments of the present invention provide a handover method, a core network device, an access network device, and a terminal device to provide a more effective handover solution when the network structure changes.

  According to one aspect, embodiments of the present invention provide a handover method. The method is applied to the communication system shown in FIG. The communication system includes a terminal device, an access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device.

  The method comprises the following steps.

  Optionally, 311. The terminal device establishes a connection with the second core network device.

  Optionally, 312. An access network device sends a first message to a second core network device, where the first message includes information about a root identifier of the first core network device or access in the first core network. Contains information about the identifier of the network device. The information about the route identifier of the first core network is used to indicate a route of a message to be transmitted by the second core network device to the first core network device.

  Optionally, 313. The second core network device receives the capability message, where the capability message is used to indicate that the terminal device supports establishing a connection with the first core network device. .

  321. The second core network device determines that the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. Further, the second core network device may determine that a switch is needed based on the conditions of the second core network device. For example, based on the load status of the second core network, no more services can be accepted. For example, the condition has exceeded a threshold. For example, the number of terminal devices currently accessing the second core network has exceeded a certain threshold. Alternatively, the switch may be triggered based on an event, for example, an event that a message sent by another network element is received. Alternatively, the switching may be triggered based on the service information of the terminal device, for example, based on the characteristics of the service currently being requested by the user of the terminal device, the terminal device may be configured to execute in the first core network. Suitable, can trigger switching.

  323. The second core network device sends a change message to the first core network device, wherein the change message indicates that a connection between the terminal device and the second core network device is a connection between the terminal device and the first core network device. Used to notify the first core network device that it needs to switch to a connection with the device. Optionally, the change message has a content such as a first key of the terminal, information about an identifier of an access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof is included. Since the second core network device has established a connection with the terminal device, the second core network device has the stored first key of the terminal device. The second core network device may obtain a route for sending a change message to the first core network based on the information about the route identifier of the first core network. Further, the second core network device sends the change message after generating the message.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct the access network device to instruct the terminal device to perform the update. Optionally, the change indication message includes information about the second key of the terminal device and / or the terminal device n identifier on the second core network interface, wherein the second key is associated with the first key. Obtained based on The identifier of the terminal device on the second core network interface includes an identifier used to identify the terminal device on the interface with which the access network device communicates with the second core network device, for example, S1 AP UE ID Can be Typically, the S1 AP UE ID includes a pair of UE identifiers. For example, the S1 AP UE ID further includes an eNB S1 AP UE ID and / or an MME S1 AP UE ID. The eNB S1 AP UE ID is an identifier used to identify a base station UE on the S1 interface, and the MME S1 AP UE ID is an identifier used to identify the MME UE on the S1 interface. It is. Similarly, the identifier may alternatively be an NG1 AP UE ID, and the identifier NG1 AP UE ID includes gNB NG1 AP UE ID and / or NG-C NG1 AP UE ID.

  After receiving the change message, the first core network device may know that the first core network device is going to accept the task of establishing a connection with the terminal, and accordingly, responds to the first core network device. The core network device prepares resources and prepares to establish communication with the terminal device. If the first core network device determines that the first core network device cannot accept the task, the first core network device may feed back a rejection message to the second core network device (not shown). ), And the second core network device may search for another core network device or another processing method based on the rejection message (not shown).

  The first key is a key used for communication between the terminal and the second core network device and adapted to the second core network technology. The first core network device estimates an adapted second key of the terminal device in the first core network based on the first key of the terminal by using a core network technology of the first core network device. I do. Correspondingly, the second key is a key used for communication between the terminal and the first core network device and adapted to the first core network technology.

  327. The first core network device sends a change indication message to the access network device. Further, the first core network device may send a change indication message to the access network device based on the information about the identifier of the access network device in the first core network.

  328. The access network device generates an update message, where the update message is used to instruct the terminal device to perform an update, and optionally, the update message indicates to the terminal device the NAS type. Used to update and / or to update the terminal key. The updated key of the terminal is obtained based on the local key stored on the terminal device. Optionally, a new key is estimated from the local key by using the same estimation method as the first core network device. The NAS of the terminal device is a function of communication between the terminal device and the core network device, and different types of NAS need to be used between the terminal device and the different types of core network devices. For example, the NAS function defined in the 3G protocol needs to be used for communication between the terminal device and the 3G core network device, and the NAS function defined in the 4G protocol is a terminal device. And the NAS function defined in the 5G protocol is used for communication between the terminal device and the 5G core network device. There is a need.

  329. The core network device notifies the terminal device of the update message.

  341. The terminal device updates the local key and / or changes the non-access layer NAS type based on the update message.

  Optionally, 331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

  Optionally, 332. The first core network device sends a release message to the second core network device, where the release message causes the second core network device to establish a connection between the terminal and the second core network device. Used to indicate release.

  The method may further comprise, as an alternative to steps 331 and 332, step 331 ′: the access network device sends a release message to the second core network device, and the release message is transmitted to the second core network device. , To indicate that the connection between the terminal and the second core network device should be released.

  Optionally, the second core network device releases a connection between the terminal and the second core network device (not shown).

  Based on the handover procedure initiated by the second core network device, the connection between the terminal and the second core network can be switched to the connection between the terminal and the first core network without switching the access network device. Can be switched, thereby efficiently fulfilling network communication requirements.

  Further, in the network communication processing, the terminal updates the terminal key and the used communication protocol in a timely manner, and completes the switching without any problem.

  A communication system, a second core network device, a first core network device, an access network device, and a terminal device using the foregoing method are disclosed separately and have similar advantages. See FIG. 3, FIG. 3-1, FIG. 3-2, FIG. 3-3, and FIG. 3-4.

  According to another aspect, embodiments of the present invention provide a handover method. The method is applied to the communication system shown in FIG. The communication system includes a terminal device, an access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device.

  The method comprises the following steps.

  Optionally, 311. The terminal device establishes a connection with the second core network by using the access network device.

  Optionally, 312. An access network device sends a first message to a second core network device, where the first message includes information about a root identifier of the first core network device or access in the first core network. Contains information about the identifier of the network device.

  421. The access network device determines that the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. Further, the access network may initiate the switch based on the conditions of the access network or the state of the second core network device. For example, the access network device infers that it can no longer accept services based on the load status of the second core network device. Alternatively, the access network device receives the message of the second core network device and is informed that a switch is needed, in which case the access network device actively determines that a switch is needed decide. It can be appreciated that the access network device may alternatively receive a message sent by another network element to trigger the switch.

  422. The access network device sends a change message to the second core network device, wherein the change message indicates that the connection between the terminal device and the second core network device is between the terminal device and the first core network device. Is used to notify the second core network device that it needs to be switched to a connection between. Optionally, the change message includes information about an identifier of the terminal on the second core network interface. The identifier of the terminal on the second core network interface is an identifier used by the access network device to identify the terminal device on the interface that communicates with the second core network device.

  Optionally, the change message may include information about a root identifier of the first core network device and / or information about an identifier of an access network device in the first core network. It can be seen that two types of information are used by the second core network device. If the second core network device learns the information or a part of the information in another way, it is not necessary to transmit the known information using step 312 or step 422. It is understood that one or both of information about the root identifier of the first core network device and information about the identifier of the access network device in the first core network may be sent by using the first message in step 312. Can be done. In this case, the change message in step 422 may not include the information sent by using the first message. Alternatively, one or both of the information about the root identifier of the first core network device and the information about the identifier of the access network device in the first core network may be sent by using the change message in step 422. In this case, the first message in step 312 may not include the information that needs to be sent by using the change message, or even step 312 may be omitted.

  423. The second core network device generates a change acknowledgment message, wherein the change acknowledgment message indicates that the connection between the terminal device and the second core network device is between the terminal device and the first core network device. Is used to notify the first core network device that it needs to be switched to a connection between them. Optionally, the change acknowledgment message includes a first key of the terminal device, information about an identifier of the access network device in the first core network, information about an identifier of the terminal device on the second core network interface, and the like. Includes one or a combination of the three items. The second core network device receives the change message, and the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. And prepare communication resources accordingly. To enable the first core network device to connect with the terminal device without any problems, the second core network device sends corresponding information. The first key of the terminal device, the information about the identifier of the access network device in the first core network, and the information about the identifier of the terminal device on the second core network interface are the same as those in the solution of FIG. Or match. Details will not be described again.

  424. The second core network device sends a change acknowledgment message to the first core network device.

  Optionally, the second core network device may discover the first core network device based on information about a root identifier of the first core network device.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct the access network device to instruct the terminal device to perform the update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is the first key Obtained based on

  327. The first core network device sends a change indication message to the access network device.

  328. The access network device generates an update message, wherein the update message is used to instruct the terminal device to perform the update, and optionally, the update message indicates to the terminal device the NAS type. Used to update and / or to update the terminal key. The updated key of the terminal is obtained based on the local key stored on the terminal device.

  329. The core network device notifies the terminal device of the update message.

  341. The terminal device updates the local key and / or changes the non-access layer NAS type based on the update message. Updating the NAS type includes updating the NAS type used to communicate with the second core network device to the NAS type used to communicate with the first core network, Updating the key includes updating a first key used to communicate with the second core network device to a second key used to communicate with the first core network. .

  Optionally, 331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

  Optionally, 332. The first core network device sends a release message to the second core network device, where the release message causes the second core network device to establish a connection between the terminal and the second core network device. Used to indicate release.

  The method may further comprise, as an alternative to steps 331 and 332, a step 331 ′: the access network device sends a release message to the second core network device, wherein the release message is transmitted to the second core network device. Used to instruct the device to release the connection between the terminal and the second core network device.

  Further, the second core network device releases the connection between the terminal and the second core network device (not shown).

  Based on the handover procedure initiated by the access network device, the connection between the terminal and the second core network may be switched to the connection between the terminal and the first core network without switching the access network device. Thus, the network communication request is efficiently satisfied.

  A communication system, a second core network device, a first core network device, an access network device, and a terminal device using the foregoing method are disclosed separately and have similar advantages. See FIGS. 4, 4-1, 4-2, 4-3, and 4-4.

  According to yet another aspect, an embodiment of the present invention provides a handover method. The method is applied to the communication system shown in FIG. The communication system includes a terminal device, a first access network device, a second access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device, and the same access network device is the first access network device.

  The method comprises the following steps.

  Optionally, 311. The terminal device establishes a connection with the second core network device by using the second access network device.

  Optionally, 312. A first access network device sends a first message to a second core network device, where the first message includes information about a root identifier of the first core network device, or a first core network device. Contains information about the identifier of the access network device in the network.

  Optionally, 313. The second core network device receives the capability message, where the capability message is used to indicate that the terminal device supports establishing a connection with the first core network device. .

  514. The second access network device generates a handover message, wherein the handover message indicates that a connection between the terminal device and the second access network device is a connection between the terminal device and the first access network device. Used to indicate that it needs to be switched to. Further, the handover message includes information about the identifier of the terminal device on the second core network interface. The identifier of the terminal device on the second core network interface includes an identifier used to identify the terminal device on the interface with which the access network device communicates with the second core network device, for example, S1 AP UE ID It may be.

  515. The second access network device sends a handover message to the first access network device.

  The second access network device sends a handover message, instructing another network element to prepare to establish a connection with the terminal.

  516. The first access network device generates a report message, wherein the report message indicates that the connection between the terminal device and the second access network device is a connection between the terminal device and the first access network device. Is used to notify the second core network device that it needs to be switched to the second core network device. Further, the report message includes information about the identifier of the terminal device on the second core network interface. Similar to the change message in the second embodiment, the report message may further include information about the root identifier of the first core network device, or information about the identifier of the access network device in the first core network.

  517. The first access network device sends a report message to the second core network device.

  521. The second core network device determines that the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device.

  523. The second core network device sends a change message to the first core network device, wherein the change message indicates that a connection between the terminal device and the second core network device is between the terminal device and the first core network device. It is used to notify the first core network device that it needs to switch to a connection with the network device. Optionally, the change message has a content such as a first key of the terminal, information about an identifier of an access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof is included.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct the terminal device to instruct the access network device to perform the update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is the first key Obtained based on

  327. The first core network device sends a change indication message to the first access network device. Further, the first core network device may send a change indication message to the access network device based on the information about the identifier of the access network device in the first core network.

  328. The first access network device generates an update message, wherein the update message is used to instruct the terminal device to perform an update, and optionally, the update message is transmitted to the terminal device by the NAS. Used to update the type and / or to update the terminal key. The updated key of the terminal is obtained based on the local key stored on the terminal device.

  529. The first access network device notifies the terminal device of the update message.

  If the first access network device has completed the inter-cell handover from the second access network device, in other words, if the first access network device has established a direct connection with the terminal device, the second access network is no longer available. It can be appreciated that the device need not be used and the first access network device may notify the terminal device of the update message directly. As an alternative solution, the first access network device may forward the update message using the second access network device (not shown), in other words, the second access network device sends the update message It can be seen that only the transfer of the update message is performed without processing.

  Optionally, the method may further comprise the second access network device sending a message (not shown) to the second access network device, the message switching to the second access network device. Has been completed and is used to indicate that the connection with the terminal device may be released. The message may be sent before or after the update message, and a similar function may instead be completed by using the information held in the update message.

  341. The terminal device updates the local key and / or changes the non-access layer NAS type based on the update message. See the solution in FIG.

  Optionally, 331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

  Optionally, 332. The first core network device sends a release message to a second core network device, where the release message causes the second core network device to establish a connection between the terminal and the second core network device. Used to indicate release.

  The method may further comprise, as an alternative to steps 331 and 332, a step 331 ′: the access network device sends a release message to the second core network device, wherein the release message is transmitted to the second core network device. Used to instruct the device to release the connection between the terminal and the second core network device.

  Optionally, the second core network device releases a connection between the terminal and the second core network device (not shown).

  Based on the handover procedure initiated by the second core network device, the connection between the terminal and the second core network can be switched to the connection between the terminal and the first core network without switching the access network device. Can be switched, thereby efficiently fulfilling network communication requirements.

  Initially, only conventional inter-cell handover is started for the terminal device. Specifically, a handover from the second access network device to the first access network device is performed. However, since the first access network device accesses the first core network device in addition to the access to the second core network device, the second core network device is further based on a conventional inter-cell handover. , Trigger a handover from the second core network device to the first core network device, thereby providing different qualities of service. For example, the UE originally performs inter-cell handover only in the 5G network. Since the target base station is an e-eNB and the base station can also access the 4G network, the 5G core network device further hands over the UE to the 4G network, and the corresponding core network device is also a 4G EPC. In the early stages of establishing a 5G network, the UE can be more quickly handed over to the 4G network by using the above solution due to the lack of 5G service capability, which allows the handover request Is satisfied.

  A communication system, a second core network device, a first core network device, a first access network device, a terminal device, and a second access network device using the foregoing method are separately disclosed and have similar advantages. . See FIG. 5, FIG. 5-1, FIG. 5-2, FIG. 5-3, FIG. 5-4, and FIG. 5-5.

  According to yet another aspect, embodiments of the present invention provide a computer-readable storage medium, wherein the computer-readable storage medium stores instructions used to perform a method used by the aforementioned communication device. However, the instructions include a program designed to perform the above aspects. The communication device may be a core network device, an access network device, or a terminal device.

  According to yet another aspect, an embodiment of the invention provides a communication device, wherein the communication device comprises a memory and a processor, wherein the memory comprises the computer readable storage medium in the preceding aspect, wherein the processor comprises: , Used to perform the method used by the communication device, and configured to execute instructions stored on the computer-readable storage medium. The communication device may be a core network device, an access network device, or a terminal device.

  According to yet another aspect, an embodiment of the present invention provides a communication system, wherein the system comprises the core network device, the access network device, and the terminal device in the aforementioned aspect.

  According to the technical solution provided in the embodiment of the present invention, a new handover solution may be provided. In the system, the first core network device and the second core network device communicate with the terminal device by using the same access network device.

FIG. 2 is a schematic diagram of two existing communication systems.

1 is a schematic diagram of a communication system according to an embodiment of the present invention.

4 is a schematic flowchart of a handover method according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a second core network device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a first core network device according to an embodiment of the present invention.

1 is a schematic diagram of an access network device according to an embodiment of the present invention.

It is a schematic diagram of a terminal device concerning an embodiment of the present invention.

4 is a schematic flowchart of a handover method according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a second core network device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a first core network device according to an embodiment of the present invention.

1 is a schematic diagram of an access network device according to an embodiment of the present invention.

It is a schematic diagram of a terminal device concerning an embodiment of the present invention.

4 is a schematic flowchart of a handover method according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a second core network device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a first core network device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a first access network device according to an embodiment of the present invention.

It is a schematic diagram of a terminal device concerning an embodiment of the present invention.

FIG. 3 is a schematic diagram of a second access network device according to an embodiment of the present invention.

1 is a schematic diagram of a communication device according to an embodiment of the present invention.

1 is a schematic diagram of a communication device according to an embodiment of the present invention.

  The embodiment of the present invention provides a solution based on the communication system shown in FIG. As shown in FIG. 2, an embodiment of the present invention provides a communication system. The communication system comprises an access network device 203 (such as an e-eNB), a first core network device 201 (such as an EPC), and a second core network device 202 (such as a NextGen core). The corresponding interface may be an S1 interface or an NG1 interface.

  The technical solutions in the embodiments of the present invention include, for example, a code division multiple access (CDMA) system, a time division multiple access (time division multiple access, TDMA) system, and a frequency division multiplexing system for data processing. Access (frequency division multiple access, FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency multiplexed access (single carrier FDMA systems, FDMA systems such as FDMA, SC-based FDMA systems, and FDMA systems such as FDMA) Can be applied to various communication systemsThe terms "system" and "network" are interchangeable. Wireless technologies such as universal terrestrial radio access (UTRA) and CDMA2000 may be implemented in a CDMA system. UTRA may include wideband CDMA (WCDMA) technology, and another technology converted from CDMA. CDMA2000 may cover the interim standard (IS) 2000 (IS-2000), the IS-95 standard, and the IS-856 standard. Wireless technologies such as global system for mobile communications (GSM) can be implemented in TDMA systems. Evolved universal terrestrial radio access (evolved UTRA, E-UTRA), ultra mobile broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMax), IEEE 802.20, flash OFDMA, etc. May be implemented in an OFDMA system. UTRA corresponds to UMT, and E-UTRA corresponds to an evolved version of UMT. A new version of UMT, E-UTRA, is used in 3GPP long term evolution (LTE) and various versions that have evolved based on LTE. The fifth generation (5th Generation, short "5G") communication system and New Radio (New Radio, short "NR") are the next generation communication systems under study. In addition, the communication system 200 is further applicable to future communication technologies to which the technical solutions provided in the embodiments of the present invention can be applied. The system architecture and service scenarios described in the embodiments of the present invention are intended to more clearly describe the technical solutions in the embodiments of the present invention, but are provided in the embodiments of the present invention. It is not intended to limit the technical solutions. Those skilled in the art may know that as the network architecture evolves and new service scenarios emerge, the technical solutions provided in the embodiments of the present invention are further applicable to similar technical problems.

  A terminal device, also referred to as a user equipment (User Equipment, UE), a mobile terminal (Mobile Terminal, MT), a mobile user equipment, or the like, is connected via a radio access network (eg, Radio Access Network, RAN) to a terminal device. It may communicate with one or more core networks. The user equipment may be a mobile terminal such as a mobile phone (also referred to as a "cellular" phone) or a computer having a mobile terminal. For example, the user equipment may be portable, pocket-sized, handheld, self-contained, or on-board mobile.

  The access network device may be an apparatus arranged in a wireless access network for providing a terminal device with a wireless communication function. A network may include macro base stations, micro base stations (also referred to as small cells), relay nodes, access points, and the like in various forms, and also includes various forms of control nodes such as network controllers. obtain. A control node may be connected to multiple base stations and configure resources for multiple terminal devices included in the coverage of multiple base stations. In a system using different wireless access technologies, devices having the function of an access network device may have different names, for example, may correspond to base stations and base station controllers in 2G, or may correspond to base stations and base stations in 3G. It corresponds to eNB or eNodeB in RNC or LTE, or base station in 5G (there is no official name at present, for example, G-NB or NX-NB) or NR, or transmission / reception point (Transmission Reception Point, abbreviated) "TRP"). This is not limited in the present invention.

  The core network device may be a device used in the core network after the access network device, and is usually connected to the access network device, and there may be a plurality of core network devices based on functions. In a system using different wireless connection technologies, devices having the function of the core network device may have different names, for example, corresponding to MME or S-GW in LTE, or corresponding to SGSN / GGSN in 3G. Often, there is no official name in 5G such as NG-Core.

  [First Embodiment]

  Embodiments of the present invention provide a handover method. The method is applied to the communication system shown in FIG. The communication system includes a terminal device, an access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device. Further, the first core network device and the second core network device may use different core network technologies. For example, the first core network device may use LTE core network technology and the second core network device may use 5G core network technology. For another example, the first core network device may use 5G core network technology and the second core network device may use LTE core network technology.

  As shown in FIG. 3, the method comprises the following steps.

  311. A terminal device establishes a connection with the second core network device. The terminal device may establish a connection with the second core network device in a known manner. Typically, the terminal device establishes a connection with the second core network device by using the access network device. However, those skilled in the art will appreciate that the connection may be established in another manner. For example, the terminal device sends the message directly to the second core network device.

  312. The access network device sends a first message to a second core network device, where the first message includes information about a root identifier of the first core network device or access in the first core network. Contains information about the identifier of the network device. The information about the route identifier of the first core network is used to indicate a route of a message to be transmitted by the second core network device to the first core network device. For example, the information on the route identifier of the first core network may be information including the tracking area code TAC. The information about the identifier of the access network device in the first core network may be information about the identifier of the access network device when the access network device communicates with the first core network device. It can be appreciated that the information about the identifier may be an identifier, or may be an index or other information. The information about the root identifier of the first core network device and the information about the identifier of the access network device in the first core network are information that can be used by the second core network device, and are not necessarily the first message. It should be noted that it need not be sent by using. The first message may be known to the second core network device when the second core network device may obtain one of the two pieces of information in another manner, eg, by agreement. It can be appreciated that the information may not be included. Of course, the first message may instead include information about the root identifier of the first core network device and information about the identifier of the access network device in the first core network. Since the first core network device and the second core network device communicate with the terminal device by using the same access network device, the access network device is related to the first core network device, ie, the first core network device. It can be appreciated that knowing the information that can be included in the message.

  313. The second core network device receives the capability message, where the capability message is used to indicate that the terminal device supports establishing a connection with the first core network device. . It can be appreciated that the capability message may be sent by the terminal device to the second core network device or may be sent by the access network device to the second core network device. For example, the capability message may be a non-access layer NAS type message.

  321. The second core network device determines that the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. Further, the second core network device may determine that a switch is needed based on the conditions of the second core network device. For example, based on the load status of the second core network, no more services can be accepted. For example, the condition has exceeded a threshold. Alternatively, the switch may be triggered based on an event, for example, an event that a message sent by another network element is received.

  323. The second core network device sends a change message to the first core network device, wherein the change message indicates that a connection between the terminal device and the second core network device is between the terminal device and the first core network device. Used to notify the first core network device that it needs to be switched to a connection with the core network device. Optionally, the change message has a content such as a first key of the terminal, information about an identifier of an access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof is included. Since the second core network device has established a connection with the terminal device, the second core network device has stored the first key of the terminal device. The second core network device may obtain a route for transmitting the change message to the first core network based on the information about the route identifier of the first core network. Further, the second core network device sends the change message after generating the message. Information about the terminal device identifier on the second core network interface may be used to indicate which terminal device needs to be processed. The identifier of the terminal device on the second core network interface includes an identifier used to identify the terminal device on the interface with which the access network device communicates with the second core network device, for example, S1 AP UE ID It may be.

  The second core network may use a change message to notify another network element that a switch is needed and trigger subsequent procedures.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct an access network device to instruct a terminal device to perform an update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is based on the first key. Is obtained.

  After receiving the change message, the first core network device knows that the first core network device is going to accept the task of establishing a connection with the terminal, and correspondingly, the first core network device The network device prepares resources and prepares to establish communication with the terminal device. If the first core network device determines that the first core network device cannot accept the task, the first core network device may feed back a rejection message to the second core network device (not shown). ) And the second core network device searches for another core network device or another processing method based on the rejection message (not shown).

  The first key is a key used for communication between the terminal and the second core network device and adapted to the second core network technology. The first core network device estimates an adapted second key of the terminal device in the first core network based on the first key of the terminal by using a core network technology of the first core network device. I do.

  327. The first core network device sends a change instruction message to the access network device. Further, the first core network device may send a change indication message to the access network device based on the information about the identifier of the access network device in the first core network.

  328. The access network device generates an update message, where the update message is used to instruct the terminal device to perform an update, and optionally, the update message indicates to the terminal device the NAS type. Used to update and / or to update the terminal's key. The updated key of the terminal is obtained based on the local key stored on the terminal device. Optionally, the new key is estimated from the local key by using the same estimation method as that of the first core network device.

  The access network device may know the terminal device whose key needs to be updated based on the information about the identifier of the terminal device on the second core network interface. When communicating with the terminal device, the access network device receives the second key and stores it locally, like using the second key.

  329. The core network device notifies the terminal device of the update message.

  341. The terminal device updates the local key and changes the non-access layer NAS type based on the update message. Updating the NAS type includes updating the NAS type used to communicate with the second core network device to the NAS type used to communicate with the first core network, Updating the key includes updating a first key used to communicate with the second core network device to a second key used to communicate with the first core network. . Further, the local key of the terminal device is used to communicate with the second core network device, and the key now needs to be updated. Specifically, there is a mapping relationship between the local key of the terminal device and the first key of the terminal device on the second core network device. The mapping relationship may be such that the first key is the same as the second key, or the first key may be obtained by an operation. Since the first core network device has updated the first key on the network side with a second key that satisfies the request of the first core network device, the terminal device needs to obtain a new key in the corresponding estimation scheme. This satisfies the request for communicating with the first core network device. Correspondingly, instead of satisfying the request to communicate with the second core network device, the original NAS type also needs to be updated to satisfy the request to communicate with the first core network device. For example, a 5G NAS type is updated to a 4G NAS type.

  331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

  332. The first core network device sends a release message to a second core network device, where the release message releases a connection between the terminal and the second core network device to the second core network device. Used to instruct

  The method may further include, as an alternative to steps 331 and 332, step 331 ': the access network device sends a release message to the second core network device, wherein the release message is transmitted to the second core network device. To release the connection between the terminal and the second core network device.

  Further, the second core network device releases the connection between the terminal and the second core network device (not shown).

  Based on the handover procedure initiated by the second core network device, the connection between the terminal and the second core network can be switched to the connection between the terminal and the first core network without switching the access network device. Can be switched, thereby efficiently fulfilling network communication requirements.

  Further, in the network communication processing, the terminal updates the key of the terminal and the communication protocol to be used in a timely manner, and completes the switching without any problem.

  In the flowchart of FIG. 3, the dashed lines indicate that the steps are optional. Specifically, one of steps 311, 312, 313 and 313 'or a combination thereof may be omitted, and one of steps 331, 332 and 331' or a combination thereof may be omitted. Specifically, when the second core network device knows information about the root identifier of the first core network device or information about the identifier of the access network device in the first core network, step 312 is omitted. In other words, the first message need not be sent. When the second core network device knows that the terminal device supports that the terminal device establishes a connection with the first core network device, steps 313 and 313 ′ may be omitted, in other words, No capability information needs to be sent. Steps 331, 332 and 331 'are omitted so as to release the connection between the terminal and the second core network device when the second core network device has a suitable mechanism, for example a timeout mechanism. In other words, the release message need not be sent to release resources. It can be seen that omitting the foregoing steps does not affect the technical effect of the solution of FIG. 3 and does not affect the function of the various network elements.

  The following different methods can be obtained for the various network elements of FIG. The following method is consistent with the method of FIG. 3 and the same parts will not be described again in detail. The steps of the method of FIG. 3 and the associated description may provide a reference to the following method and have similar advantages as the following method. Details will not be described again for brevity. In the following method, it can be understood that the first core network device and the second core network device communicate with the terminal device by using the same access network device.

  The handover method is used by the second core network device and includes the following steps.

  321. The second core network device determines that the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device.

  323. The second core network device sends a change message to the first core network device, wherein the change message indicates that a connection between the terminal device and the second core network device is between the terminal device and the first core network device. It is used to notify the first core network device that it needs to switch to a connection with the network device. Optionally, the change message has a content such as a first key of the terminal, information about an identifier of an access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof is included.

  The second core network device determines that a switch is needed, sends a change message, and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the following steps: 311. The terminal device establishes a connection with the second core network device.

  Further, the handover method further comprises the step of the second core network device receiving the first message, wherein the first message includes information about the root identifier of the first core network device, or the first message. And / or wherein the second core network device receives the capability message including information about an identifier of the access network device in the core network, wherein the capability message indicates that the terminal device has the first core. Used to indicate that the terminal device supports establishing a connection with the network device.

  The second core network device knows the information needed in the handover process by using the first message or the capability message and prepares well for the handover procedure.

  Further, the handover method further comprises the step of the second core network device receiving a release message, wherein the release message provides the second core network device with a connection between the terminal and the second core network device. Used to indicate release.

  Further, the handover method further comprises the second core network device releasing the connection between the terminal and the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

  The handover method is used by a first core network device, wherein the first core network receives a change message, wherein the change message is transmitted to the first core network device by a terminal device and a second core network device. Used to signal that a connection between the terminal device and the first core network device needs to be switched between the terminal device and the first core network device. Optionally, the change message includes content such as a first key of the terminal, information about an identifier of an access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct an access network device to instruct a terminal device to perform an update. The change indication message may include information about the second key of the terminal device and / or the identifier of the terminal device on the second core network interface, wherein the second key is obtained based on the first key. Is done.

  327. The first core network device sends a change instruction message to the access network device.

  By receiving the change message, the first core network device may know that the first core network device needs to connect to the terminal device, and the first core network device sends the change instruction message to the terminal device. By using it, it may be known that the first core network device and the second core network device may inform another network element that the first core network device and the second core network device are sufficiently prepared for switching. . In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the first core network device receiving an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch. It has a stage.

  332. The first core network device sends a release message to the second core network device, where the release message causes the second core network device to establish a connection between the terminal and the second core network device. Used to indicate release.

  Based on the release procedure described above, the first core network device can help the second core network device complete the resource release, saving resources.

  A handover method is used by the access network device, wherein the access network device receives a change indication message, the change indication message instructing the access network device to instruct the terminal device to perform the update. , Which is used for Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface.

  328. The access network device generates an update message, where the update message is used to instruct the terminal device to perform the update. Optionally, the update message is used to instruct the terminal device to update the NAS type and / or to update the terminal's key.

  329. The core network device notifies the terminal device of the update message.

  The access network device may know by receiving the change indication message that the second core network device and the first core network device are well prepared for the switch. The access network device may initiate an update procedure at the terminal side by generating and transmitting an update message to satisfy the requirements of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the access network device transmitting a first message, wherein the first message is information about a root identifier of the first core network device or in the first core network. Comprising information about an identifier of the access network device.

  By using the first message, the access network device may inform another network element of the information needed in the handover process and prepare well for the handover procedure.

  Further, the handover method further includes the following steps.

  331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

  Further, the handover method further includes the following steps.

  331 '. The access network device sends a release message to the second core network device, where the release message causes the second core network device to release the connection between the terminal and the second core network device. Used to indicate.

  Based on the release procedure described above, the first access network device may help the second core network device to complete the resource release, saving resources.

  A handover method is used by the terminal device, the terminal device receiving an update message, wherein the update message is used to instruct the terminal device to perform an update, and optionally, the update message Used to instruct the terminal device to update the NAS type and / or update the terminal's key, the steps and the terminal device's updating the NAS type and / or updating the terminal's key And a stage.

  Updating the NAS type includes updating the NAS type used for communicating with the second core network device to the NAS type used for communicating with the first core network, and updating the key of the terminal. Updating includes updating a first key used to communicate with the second core network device to a second key used to communicate with the first core network.

  The terminal may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message, satisfying a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the terminal device transmitting a capability message, wherein the capability message indicates that the terminal device supports that the terminal device establishes a connection with the first core network device. , Which are used for

  The terminal informs another network element that the terminal may support communication with the first core network device by using the capability information to fully prepare for the switch.

  Embodiments of the present invention provide a communication system. The communication system includes a terminal device, an access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device. The system may use the handover method shown in FIG. Further, the first core network device and the second core network device may use different core network technologies. For example, the first core network device may be a core network device using an LTE core network technology standard, and the second core network device may be a core network device using a 5G core network technology standard.

  The following devices may relate to the steps of the method described in FIG. Thus, the method steps and related description in FIG. 3 may provide a reference to the following devices and have similar advantages. Details will not be described again for brevity. In the following method, it can be understood that the first core network device and the second core network device communicate with the terminal device by using the same access network device.

  As shown in FIG. 3A, the second core network device 390 is configured such that a connection between the terminal device and the second core network device is a connection between the terminal device and the first core network device. A processing unit 3901 configured to determine that the first core network device and the second core network device communicate with a terminal device by using the same access network device. A unit 3901 and a transceiver unit 3902 configured to send a change message to a first core network device, the change message comprising: a connection between the terminal device and the second core network device; Between the first core network device That need to be switched to the connection used to notify the first core network device, and a transmitting and receiving unit 3902.

  Optionally, the change message has a content such as a first key of the terminal, information about an identifier of an access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof is included.

  The second core network device determines that a switch is needed, sends a change message, and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, in the second core network device, the terminal device establishes a connection with the second core network device.

  Further, at the second core network device, the transmitting / receiving unit is configured to receive the first message, wherein the first message includes information about a root identifier of the first core network device, or The information includes information about an identifier of an access network device in one of the core networks, and / or the transmitting / receiving unit is configured to receive the capability message, wherein the capability message indicates that the terminal device is in communication with the first core network device. Is used to indicate that the terminal device supports establishing a connection.

  The second core network device may know the information needed in the handover process by using the first message or the capability message to fully prepare for the handover procedure.

  Further, at the second core network device, the transceiver unit is configured to receive a release message, wherein the release message is transmitted to the second core network device between the terminal and the second core network device. Used to indicate that the connection should be released.

  Further, at the second core network device, the processing unit is configured to release a connection between the terminal and the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

  As shown in FIG. 3-2, the first core network device 380 is a transmission / reception unit 3802 configured to receive a change message, wherein the change message comprises a terminal device and a second core network device. The first core network device is used to notify the first core network device that the connection between the first core network device and the first core network device needs to be switched to a connection between the terminal device and the first core network device. And the second core network device communicates with the terminal device by using the same access network device, and optionally, the change message includes the first key of the terminal, the access key of the access network device in the first core network. Information about the identifier, and the second core network A sending / receiving unit 3802 including at least one or a combination thereof, such as information about an identifier of a terminal device on a network interface, and a processing unit 3801 configured to generate a change instruction message, the change instruction message comprising: Is used to instruct the access network device to instruct the terminal device to perform an update, and optionally, the change indication message comprises a second key of the terminal device and / or a second core network. The second key includes information about the identifier of the terminal device on the interface, and the processing unit 3801 is obtained based on the first key.

  The transmitting / receiving unit 3802 is further configured to send a change indication message to the access network device.

  The first core network device may know by receiving the change message that the first core network device needs to connect to the terminal device, and the first core network device By using the change indication message to satisfy the request, another network element may be notified that the first core network device and the second core network device are fully prepared for the switch. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, at the core network device, the transceiver unit is configured to receive an acknowledgment message, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch. The transceiver unit is configured to send a release message to the second core network device, where the release message releases a connection between the terminal and the second core network device to the second core network device. Used to instruct

  Based on the release procedure described above, the first core network device can help the second core network device complete the resource release, saving resources.

  As shown in FIG. 3-3, the access network device 370 is a transceiver unit 3702 configured to receive a change indication message, wherein the change indication message causes the access network device to perform an update. The first core network device and the second core network device are used to instruct the terminal device to indicate, the first core network device and the second core network device communicate with the terminal device by using the access network device, and optionally, a change instruction message. Is a transmitting / receiving unit 370 including information about the terminal device's second key and / or the identifier of the terminal device on the second core network interface, and a processing unit 3701 configured to generate an update message. Update message The update message is used to instruct the terminal device to perform an update, and optionally, the update message instructs the terminal device to update the NAS type and / or to update the terminal key. And a processing unit 3701 used to perform the processing.

  The sending / receiving unit 3702 is further configured to send the update message to the terminal device.

  The access network device may know by receiving the change indication message that the second core network device and the first core network device are well prepared for the switch. The access network device may initiate an update procedure at the terminal side by generating and sending an update message to satisfy the requirements of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, at the access network device, the processing unit 3701 is configured to generate a first message, wherein the first message is information about a root identifier of the first core network device, or a first core network device. The transceiver unit 3702 includes information about an identifier of an access network device in the network, and is configured to transmit the first message.

  The access network device may inform another network element of the information needed in the handover process by using the first message to be fully prepared for the handover procedure.

  Further, at the access network device, the processing unit 3701 is configured to generate an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch. , The transceiver unit 3702 is configured to send an acknowledgment message to the first core network device.

  Further, at the access network device, the processing unit 3701 is configured to generate a release message, wherein the release message causes the second core network device to establish a connection between the terminal and the second core network device. Used to indicate release, the transceiver unit 3702 is configured to transmit a release message to the second core network device.

  Based on the release procedure described above, the first access network device may help the second core network device to complete the resource release, saving resources.

  As shown in FIGS. 3-4, the terminal device is a transmitting / receiving unit 3602 configured to receive an update message, wherein the update message informs the terminal device of the NAS type and / or And a processing unit 3601 configured to update the NAS type and / or update the key of the terminal, where the NAS type is used to indicate that the NAS type is to be updated. Updating includes updating the NAS type used to communicate with the second core network device to the NAS type used to communicate with the first core network, and updating the key of the terminal. To do so, the first key used to communicate with the second core network device is transmitted to the first core network device. It includes updating the second key used to communicate with the workpiece, the first core network device and a second core network device communicates with the terminal device by using the same access network device.

  The terminal may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message to satisfy a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, at the terminal device, the processing unit is configured to generate a capability message, wherein the capability message indicates that the terminal device supports that the terminal device establishes a connection with the first core network device. Used for indicating, the transceiver unit is configured to transmit a capability message.

  The terminal informs another network element that the terminal may support communication with the first core network device by using the capability message to be fully prepared for the switch.

  [Second embodiment]

  Embodiments of the present invention provide a handover method. The method is applied to the communication system shown in FIG. The communication system includes a terminal device, an access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device. It can be seen that the second embodiment is basically the same as the first embodiment. The differences are as follows. In the first embodiment, the second core network device needs to switch a connection between the terminal device and the second core network device to a connection between the terminal device and the first core network device. However, in the second embodiment, the access network device determines that switching is required.

  Based on the handover procedure initiated by the access network device, the connection between the terminal and the second core network may be switched to the connection between the terminal and the first core network without switching the access network device. Thus, the network communication request is efficiently satisfied.

  For simplicity of description, the same reference numbers are used for the same parts in FIGS. Therefore, details will not be described again. The different parts, such as steps 421, 422, 423 and 424, are described in detail. It can be understood that the related description of FIG. 3 can be used to describe the technical solution of FIG.

  As shown in FIG. 4, the method includes the following steps.

  311. The terminal device establishes a connection with the second core network by using the access network device.

  312. An access network device sends a first message to a second core network device, where the first message includes information about a root identifier of the first core network device or access in the first core network. Contains information about the identifier of the network device.

  421. The access network device determines that a connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. Further, the access network may initiate the switch based on the conditions of the access network or the state of the second core network device. For example, the access network device infers that it can no longer accept services based on the load status of the second core network device. Instead, the access network device receives the message of the second core network device and is informed that a switch is needed, in which case the access network device is active when the switch is needed decide. It can be appreciated that the access network device may instead receive a message sent by another network element to trigger the switch.

  422. The access network device sends a change message to the second core network device, wherein the change message indicates that the connection between the terminal device and the second core network device is different from the terminal device and the first core network device. It is used to notify the second core network device that it needs to be switched to a connection between. Optionally, the change message includes information about an identifier of the terminal on the second core network interface. The identifier of the terminal on the second core network interface is an identifier used by the access network device to identify the terminal device on the interface that communicates with the second core network device.

  Optionally, the change message may include information about a root identifier of the first core network device and / or information about an identifier of an access network device in the first core network. It can be appreciated that two types of information are used by the second core network device. If the second core network device learns the information or part of the information in another way, it is unnecessary to send the known information by using step 312 or step 422. One or both of the information about the root identifier of the first core network device and the identifier of the access network device in the first core network may be sent by using the first message in step 312. Can be understood. In this case, the change message in step 422 may not include the information sent by using the first message. Alternatively, one or both of the information about the root identifier of the first core network device and the information about the identifier of the access network device in the first core network may be sent by using a change message in step 422. In this case, the first message in step 312 may not include the information that needs to be sent by using the change message, or even step 312 may be omitted.

  423. The second core network device generates a change acknowledgment message, wherein the change acknowledgment message indicates that the connection between the terminal device and the second core network device is different from the terminal device and the first core network device. Is used to notify the first core network device that it needs to be switched to a connection between the first core network device. Optionally, the change acknowledgment message is a terminal device's first key, information about an identifier of an access network device in a first core network, and information about an identifier of the terminal device on a second core network interface. , And one or a combination thereof. The second core network device receives the change message, and the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. Knowing that, prepare communication resources accordingly. The second core network device sends corresponding information so as to allow the first core network device to connect to the terminal device without any problem. The first key of the terminal device, the information about the identifier of the access network device in the first core network, and the information about the identifier of the terminal device on the second core network interface are similar to those of the solution in FIG. Or matches. Details will not be described again.

  424. The second core network device sends a change acknowledgment message to the first core network device.

  Optionally, the second core network device may discover the first core network device based on information about a root identifier of the first core network device.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct the access network device to instruct the terminal device to perform the update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is the first key Obtained based on

  327. The first core network device sends a change indication message to the access network device.

  328. The access network device generates an update message, where the update message is used to instruct the terminal device to update the NAS type and / or to update the terminal key. The updated key of the terminal is obtained based on the local key stored on the terminal device.

  329. The core network device notifies the update message to the terminal device, wherein the update message is used to instruct the terminal device to perform the update, and optionally, the update message Used to update the NAS type and / or to update the terminal's key.

  341. The terminal device updates the local key and / or changes the non-access layer NAS type based on the update message.

  331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

  332. The first core network device sends a release message to a second core network device, wherein the release message informs the second core network device of a connection between the terminal and the second core network device. Used to indicate that the

  The method may further comprise, as an alternative to steps 331 and 332, step 331 ′: the access network device sends a release message to the second core network device, wherein the release message is To release the connection between the terminal and the second core network device.

  Further, the second core network device releases the connection between the terminal and the second core network device (not shown).

  Based on the handover procedure initiated by the access network device, the connection between the terminal and the second core network may be switched to the connection between the terminal and the first core network without switching the access network device. Thus, the network communication request is efficiently satisfied.

  In the flowchart of FIG. 4, the dashed lines indicate that the steps are optional. Specifically, one of steps 311, 312, 313 and 313 'or a combination thereof may be omitted, and one of steps 331, 332 and 331' or a combination thereof may be omitted. .

  The following different methods can be obtained for the various network elements of FIG. The following method is consistent with the method of FIG. 4, and the same parts will not be described again in detail. The steps of the method and the associated description in FIGS. 3 and 4 may provide a reference to the following method and have similar advantages as the following method. Details will not be described again for brevity. In the following method, it can be understood that the first core network device and the second core network device communicate with the terminal device by using the same access network device.

  The handover method is used by a second core network device, wherein the second core network device receives a change message, the change message comprising a connection between the terminal device and the second core network device. Is used to notify the second core network device that it needs to be switched to a connection between the terminal device and the first core network device. Optionally, the change message includes information about an identifier of the terminal on the second core network interface, wherein the identifier of the terminal on the second core network interface indicates that the access network device is This is an identifier used to identify a terminal device on an interface that performs communication.

  423. The second core network device generates a change acknowledgment message, wherein the change acknowledgment message indicates that the connection between the terminal device and the second core network device is different from the terminal device and the first core network device. Used to notify the first core network device that it may need to be switched to a connection between the first core network device. Optionally, the change acknowledgment message is a terminal device's first key, information about an identifier of an access network device in a first core network, and information about an identifier of the terminal device on a second core network interface. , And one or a combination thereof.

  424. The second core network device sends a change acknowledgment message to the first core network device.

  The second core network device sends a change message and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method may further comprise the following steps: 311. The terminal device establishes a connection with the second core network device.

  Further, the handover method further comprises the step of the second core network device receiving the first message, wherein the first message includes information about the root identifier of the first core network device, or the first message. Comprising information about an identifier of an access network device in the core network.

  The second core network device may know the information needed in the handover process by using the first message to fully prepare for the handover procedure.

  Further, the handover method further comprises the step of the second core network device receiving a release message, wherein the release message causes the second core network device to establish a connection between the terminal and the second core network device. Comprising a step used to indicate release.

  Further, the handover method further comprises the second core network device releasing the connection between the terminal and the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

  A handover method is used by a first core network device, wherein the first core network receives a change acknowledgment message, wherein the change acknowledgment message is transmitted between the terminal device and the second core network device. Is used to notify the first core network device that the connection of the first core network device needs to be switched to a connection between the terminal device and the first core network device. Optionally, the change acknowledgment message is a terminal device's first key, information about an identifier of an access network device in a first core network, and information about an identifier of the terminal device on a second core network interface. , And one or a combination thereof.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct an access network device to instruct a terminal device to perform an update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device identifier on the second core network interface, wherein the second key is based on the first key. Is obtained.

  327. The first core network device sends a change indication message to the access network device.

  The first core network device may know that the first core network device needs to connect with the terminal device by receiving the change acknowledgment message, and the first core network device may send a request for the network. By using the change indication message to satisfy, another network element may be notified that the first core network device and the second core network device are fully prepared for the switch. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the first core network device receiving an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch. Provided with a stage.

  332. The first core network device sends a release message to a second core network device, where the release message releases a connection between the terminal and the second core network device to the second core network device. Used to instruct

  Based on the release procedure described above, the first core network device can help the second core network device complete the resource release, saving resources.

  A handover method is used by an access network device and comprises the following steps.

  421. The access network device determines that the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device.

  422. The access network device sends a change message to the second core network device, wherein the change message indicates that the connection between the terminal device and the second core network device is between the terminal device and the first core network device. Is used to notify the second core network device that it needs to be switched to a connection between. The change message includes information about an identifier of the terminal on the second core network interface, wherein the identifier of the terminal on the second core network interface is on an interface with which the access network device communicates with the second core network device. This is an identifier used to identify the terminal device.

  The access network device determines that a switch is needed, sends a change message, and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the access network device transmitting a first message, wherein the first message includes information about a root identifier of the first core network device or access in the first core network. Comprising information about the identifier of the network device.

  The access network device may inform another network element of the information needed in the handover process by using the first message so as to be fully prepared for the handover procedure.

  Further, the handover method further comprises the step of the access network device receiving a change indication message, wherein the change indication message is used to instruct the access network device to instruct the terminal device to perform the update, It has a stage. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface.

  328. The access network device generates an update message, wherein the update message is used to instruct the terminal device to perform the update, and optionally, the update message indicates to the terminal device the NAS type. Used to update and / or to update the terminal key. The updated key of the terminal is obtained based on the local key stored on the terminal device.

  329. The core network device notifies the terminal device of the update message.

  The access network device may know by receiving the change indication message that the second core network device and the first core network device are well prepared for the switch. The access network device may initiate an update procedure at the terminal side by generating and sending an update message to satisfy the requirements of the network.

  Further, the handover method further includes the following steps.

  331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

  Further, the handover method further includes the following steps.

  331 '. The access network device sends a release message to the second core network device, wherein the release message instructs the second core network device to release the connection between the terminal and the second core network device. Used to

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

  The handover method is used by the terminal device, wherein the terminal device receives the update message, wherein the update message is used to instruct the terminal device to perform the update, and optionally, the update message is Steps used to instruct the terminal device to update the NAS type and / or to update the terminal key, and the terminal device updating the NAS type and / or updating the terminal key And

  Updating the NAS type includes updating the NAS type used to communicate with the second core network device to the NAS type used to communicate with the first core network, Updating the key includes updating a first key used to communicate with the second core network device to a second key used to communicate with the first core network. .

  The terminal may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message to satisfy a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Embodiments of the present invention provide a communication system. The communication system includes a terminal device, an access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device. The system may use the handover method shown in FIG. Further, the first core network device and the second core network device may use different core network technologies. See the description in FIG.

  The following device may relate to the steps of the method described in FIG. Accordingly, the method steps and the associated description in FIGS. 3 and 4 may provide reference to, and have similar advantages to, the following devices. Details will not be described again for brevity. In the following method, it can be understood that the first core network device and the second core network device communicate with the terminal device by using the same access network device.

  As shown in FIG. 4A, the second core network device 490 is a transmitting / receiving unit 4902 configured to receive a change message, wherein the change message is transmitted to the terminal device and the second core network device. Used to notify the second core network device that the connection between the terminal device and the first core network device needs to be switched to the connection between the terminal device and the first core network device. The message includes information about an identifier of a terminal on the second core network interface, wherein the identifier of the terminal on the second core network interface is on an interface on which the access network device communicates with the second core network device. An identifier used to identify the terminal device A sending / receiving unit 4902 and a processing unit 4901 configured to generate a change acknowledgment message, wherein the change message indicates that a connection between the terminal device and the second core network device is between the terminal device and the first core network device. Used to notify the second core network device that the connection to the core network device needs to be switched, and optionally the change acknowledgment message is the first key of the terminal device. Processing unit 4901 including one or a combination of three items: information about an identifier of an access network device in a first core network, and information about an identifier of a terminal device on a second core network interface. And

  The transmitting / receiving unit 4902 is further configured to send a change acknowledgment message to the first core network device.

  The second core network device sends a change message and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, in the second core network device, the terminal device establishes a connection with the second core network device.

  Further, at the second core network device, the transmitting / receiving unit is configured to receive the first message, wherein the first message is information about a root identifier of the first core network device, or the first message. Information about the identifier of the access network device in the core network of the network.

  The second core network device may know the information needed in the handover process by using the first message to fully prepare for the handover procedure.

  Further, at the second core network device, the transceiver unit is configured to receive a release message, wherein the release message is transmitted to the second core network device between the terminal and the second core network device. Used to indicate that the connection should be released.

  Further, at the second core network device, the processing unit is configured to release a connection between the terminal and the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

  As shown in FIG. 4-2, the first core network device 480 is a transceiver unit 4802 configured to receive a change acknowledgment message, wherein the change acknowledgment message is Is used to notify the first core network device that the connection between the first core network device and the connection between the terminal device and the first core network device needs to be switched to a connection between the terminal device and the first core network device. In particular, the change acknowledgment message includes three information, such as a first key of the terminal device, information about an identifier of the access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. Contains one or a combination of the two items A transmitting / receiving unit 4802 and a processing unit 4801 configured to generate a change indication message, wherein the change indication message is used to instruct an access network device to instruct a terminal device to perform an update; Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is the first key And a processing unit 4801 obtained based on the information.

  The transmitting / receiving unit 4802 is further configured to send a change indication message to the access network device.

  The first core network device may know that the first core network device needs to connect with the terminal device by receiving the change acknowledgment message, and the first core network device may perform the change indication message. By using, the first core network device and the second core network device can be notified to another network element that they are well prepared for the switch to satisfy the demands of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, in the first core network device, the transmitting / receiving unit receives an acknowledgment message used to indicate that the access network device and the terminal device have completed the switch, and sends the terminal to the second core network device. A release message used to instruct to release the connection with the second core network device is configured to be transmitted to the second core network device.

  Based on the release procedure described above, the first core network device can help the second core network device complete the resource release, saving resources.

  As shown in FIG. 4-3, the access network device 470 switches the connection between the terminal device and the second core network device to the connection between the terminal device and the first core network device. A processing unit 4701 configured to determine that the change message needs to be sent to the second core network device, and a transmit / receive unit 4702 configured to send the change message to the second core network device, the change message comprising: A transmitting / receiving unit 4702 used to notify the second core network device that the connection between the network device needs to be switched to the connection between the terminal device and the first core network device; including. Optionally, the change message includes information about an identifier of the terminal on the second core network interface, wherein the identifier of the terminal on the second core network interface indicates that the access network device is This is an identifier used to identify a terminal device on an interface that performs communication.

  The access network device determines that a switch is needed, sends a change message, and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, at the access network device, the transceiver unit 4702 is configured to transmit a first message, wherein the first message is information about a root identifier of the first core network device, or a first core network device. Contains information about the identifier of the access network device in the network.

  By using the first message, the access network device can inform another network element of the information needed in the handover process and prepare it well for the handover procedure.

  Further, at the access network device, the transceiver unit 4702 is configured to receive a change indication message, wherein the change indication message is for instructing the access network device to instruct the terminal device to perform an update. Used. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface.

  The processing unit 4701 is configured to generate an update message, where the update message is used to instruct a terminal device to perform an update, and optionally, the update message is transmitted to the terminal device. Used to update the NAS type and / or to update the terminal key.

  The transmitting / receiving unit 4702 is configured to notify the terminal device of the update message.

  The access network device may know by receiving the change indication message that the second core network device and the first core network device are well prepared for the switch. The access network device may initiate an update procedure at the terminal side by generating and sending an update message to satisfy the needs of the network.

  Further, at the access network device, the processing unit 4701 is configured to generate an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch. , The transceiver unit 4702 is configured to send an acknowledgment message to the first core network device.

  Further, at the access network device, the processing unit 4701 is configured to generate a release message, wherein the release message informs the second core network device of the connection between the terminal and the second core network device. Used to indicate the release, and the transmission / reception unit 4702 is configured to send a release message to the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

  As shown in FIGS. 4-4, the terminal device is a transceiver unit 4602 configured to receive the update message, wherein the update message is used to instruct the terminal device to perform the update. And optionally, the transmit / receive unit 4602 and the NAS type used to instruct the terminal device to update the NAS type and / or to update the terminal's key, and And / or a processing unit 4601 configured to update the terminal key.

  Updating the NAS type includes updating the NAS type used to communicate with the second core network device to the NAS type used to communicate with the first core network, Updating the key includes updating a first key used to communicate with the second core network device to a second key used to communicate with the first core network. .

  The terminal may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message, satisfying a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  [Third Embodiment]

  Embodiments of the present invention provide a handover method. The method is applied to the communication system shown in FIG. 5, wherein the communication system comprises a terminal device, a first access network device, a second access network device, a first core network device, a second And a core network device. The first core network device and the second core network device communicate with the terminal device by using the same first access network device. Further, the first core network device and the second core network device may use different core network technologies. See the description in FIG. The first access network device may be compatible with two different core network technologies.

  It can be seen that the third embodiment is partially similar to the first embodiment. The same is in that the connection between the terminal device and the second core network device needs to be switched to the connection between the terminal device and the first core network device, the difference being that the terminal device Instead of using one access network device, the first is to establish a connection with the second core network device by using the second access network device. The second access network device does not necessarily need to connect directly to the first core network device. For the sake of brevity, the same reference numbers are used for the same or similar parts in FIGS. Therefore, details will not be described again. It can be understood that the related description in FIG. 3 can be used to describe the technical solution in FIG.

  As shown in FIG. 5, the method comprises the following steps.

  311. The terminal device establishes a connection with the second core network device by using the second access network device. The terminal device may establish a connection with the second core network device in a known manner. Typically, the terminal device establishes a connection with the second core network device by using the access network device. However, those skilled in the art will appreciate that the connection may be established in another manner. For example, the terminal device sends the message directly to the second core network device.

  312. The first access network device sends a first message to a second core network device, wherein the first message includes information about a root identifier of the first core network device, or a first core network device. Contains information about the identifier of the access network device in the network. The information about the route identifier of the first core network is used to indicate a route of a message to be transmitted by the second core network device to the first core network device. See the related description in FIG.

  313. The second core network device receives the capability message, where the capability message is used to indicate that the terminal device supports establishing a connection with the first core network device. It can be appreciated that the capability message may be sent by the terminal device to the second core network device or may be sent by the first access network device to the second core network device. For example, the capability message may be a non-access layer NAS message.

  514. The second access network device generates a handover message, wherein the handover message indicates that a connection between the terminal device and the second access network device is a connection between the terminal device and the first access network device. Used to indicate that it needs to be switched to. Further, the handover message includes information about the identifier of the terminal device on the second core network interface. The identifier of the terminal device on the second core network interface includes an identifier used to identify the terminal device on the interface with which the access network device communicates with the second core network device, for example, S1 AP UE ID Can be The second access network device initiates a handover procedure between the access network devices based on the handover message. Specifically, to determine the conditions under which the second access network device needs to initiate a handover procedure between access network devices, see the related art of inter-cell handover in the prior art.

  515. The second access network device sends a handover message to the first access network device.

  The second access network device sends a handover message, instructing another network element to prepare to establish a connection with the terminal.

  516. The first access network device generates a report message, wherein the report message indicates that the connection between the terminal device and the second access network device is a connection between the terminal device and the first access network device. Is used to notify the second core network device that it needs to be switched to the second core network device. Further, the report message includes information about the identifier of the terminal device on the second core network interface. Similar to the change message in the second embodiment, the report message may further include information about the root identifier of the first core network device, or information about the identifier of the access network device in the first core network.

  517. The first access network device sends a report message to the second core network device. Steps 514 to 517 are similar to the conventional inter-cell handover procedure, in particular, the terminal device needs to be handed over from the second access network device in the second network to the first access network device. However, it can be understood that the first access network device is further connected to the first core network device and is a relatively specialized access network device.

  521. The second core network device determines that a connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. See step 321 in FIG. Details will not be described again. For example, the second core network device considers that the 5G service capability of the first access network device is insufficient and it is necessary to use the 4G service capability of the first access network device, A handover procedure between core network devices is started. Correspondingly, a handover from the second access network device to the first access network device is performed, but the network type is also changed.

  523. The second core network device sends a change message to the first core network device, wherein the change message indicates that a connection between the terminal device and the second core network device is a connection between the terminal device and the first core network device. It is used to notify the first core network device that it needs to switch to a connection with the network device. Optionally, the change message has a content such as a first key of the terminal, information about an identifier of an access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof is included. See step 323. Details will not be described again.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct the access network device to instruct the terminal device to perform the update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is the first key Obtained based on See the solution in FIG.

  327. The first core network device sends a change indication message to the first access network device. Further, the first core network device may send a change indication message to the access network device based on the information about the identifier of the access network device in the first core network.

  328. The first access network device generates an update message, wherein the update message is used to instruct the terminal device to perform an update, and optionally, the update message is transmitted to the terminal device by the NAS. Used to update the type and / or to update the terminal key. The updated key of the terminal is obtained based on the local key stored on the terminal device. Optionally, a new key is estimated from the local key by using the same estimation method as that of the first core network device.

  The access network device may know the terminal device whose key needs to be updated based on the information about the identifier of the terminal device on the second core network interface. The access network device receives and stores the second key locally such that the second key is used when communicating with the terminal device.

  529. The first access network device notifies the terminal device of the update message.

  If the first access network device has completed the inter-cell handover from the second access network device, in other words, if the first access network device has established a direct connection with the terminal device, the second access is no longer required. It may be appreciated that the first access network device may notify the terminal device of the update message directly without having to use a network device. As an alternative solution, the first access network device may use the second access network device to forward the update message (not shown), in other words, the second access network device It is only understood that the update message is forwarded without processing.

  Optionally, the method further comprises the step of the second access network device sending a message to the second access network device (not shown), wherein the message has been switched and the terminal device has May be used to indicate to the second access network device that the connection may be released. The message may be sent before the update message or after the update message, and a similar function may instead be completed by using the information held in the update message.

  341. The terminal device updates the local key and / or changes the non-access layer NAS type based on the update message. See the solution in FIG.

  331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

  332. The first core network device sends a release message to a second core network device, where the release message releases a connection between the terminal and the second core network device to the second core network device. Used to instruct

  The method may further comprise, as an alternative to steps 331 and 332, a step 331 ′: the access network device sends a release message to the second core network device, wherein the release message is transmitted to the second core network device. Used to instruct the device to release the connection between the terminal and the second core network device.

  Further, the second core network device releases the connection between the terminal and the second core network device (not shown).

  Based on the handover procedure initiated by the second core network device, the connection between the terminal and the second core network can be switched to the connection between the terminal and the first core network without switching the access network device. Can be switched, thereby efficiently fulfilling network communication requirements.

  Initially, only conventional inter-cell handover is started for the terminal device. Specifically, a handover from the second access network device to the first access network device is performed. However, in addition to accessing the second core network device, the first access network device accesses the first core network device, so that the second core network device is further based on conventional inter-cell handover. , Trigger a handover from the second core network device to the first core network device, thereby providing different qualities of service. For example, the UE originally performs the inter-cell handover only in the 5G network. Since the target base station is an e-eNB and the base station can also access the 4G network, the 5G core network device further hands over the UE to the 4G network, and the corresponding core network device is also a 4G EPC. In the early stages of establishing a 5G network, it can be seen that by using the above solution, the UE can be more quickly handed over to the 4G network due to insufficient service capabilities of 5G, It can be seen that the handover request is satisfied.

  In the flowchart of FIG. 5, the dashed lines indicate that the steps are optional. Specifically, one of steps 311, 312, 313, and 313 'or a combination thereof may be omitted, and one of steps 331, 332, and 331' or a combination thereof may be omitted. See the description in FIG.

  For the various network elements in FIG. 5, the following different methods can be obtained. The following method is consistent with the method in FIG. 5 and, for the same parts, details will not be described again. The steps of the method and the related description in FIG. 5 may provide a reference to the following method and have similar advantages as the following method. Details will not be described again for brevity. In the following method, it can be understood that the first core network device and the second core network device communicate with the terminal device by using the same first access network device.

  The handover method is used by a second core network device, wherein the second core network device receives the report message, wherein the report message indicates that a connection between the terminal device and the second access network device has been established. , Which is used to notify the second core network device that it needs to be switched to a connection between the terminal device and the first access network device. Further, the report message includes information about the identifier of the terminal device on the second core network interface.

  521. The second core network device determines that a connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device.

  523. The second core network device sends a change message to the first core network device, wherein the change message indicates that a connection between the terminal device and the second core network device is a connection between the terminal device and the first core network device. It is used to notify the first core network device that it needs to switch to a connection with the network device. Optionally, the change message has a content such as a first key of the terminal, information about an identifier of an access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof is included.

  The second core network device determines that a switch is needed, sends a change message, and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the following steps: 311. The terminal device establishes a connection with the second core network device.

  Further, the handover method further comprises the step of the second core network device receiving the first message, wherein the first message includes information about the root identifier of the first core network device, or the first message. And / or the second core network device receives the capability message including information about an identifier of the access network device in the core network, wherein the capability message indicates that the terminal device has the first core network. Comprising a step used to indicate that the terminal device supports establishing a connection with the device.

  The second core network device may know the information needed in the handover process by using the first message or the capability message to fully prepare for the handover procedure.

  Further, the handover method further comprises the step of the second core network device receiving a release message, wherein the release message provides the second core network device with a connection between the terminal and the second core network device. Comprising a step used to indicate release.

  Further, the handover method further comprises the second core network device releasing the connection between the terminal and the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

  The handover method is used by a first core network device, wherein the first core network receives a change message, wherein the change message comprises a connection between the terminal device and the second core network device. , Which is used to notify the first core network device that the connection between the terminal device and the first core network device needs to be switched. Optionally, the change message has a content such as a first key of the terminal, information about an identifier of an access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof is included.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct an access network device to instruct a terminal device to perform an update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is the first key Obtained based on

  327. The first core network device sends a change indication message to the first access network device. Further, the first core network device may send a change indication message to the access network device based on the information about the identifier of the access network device in the first core network.

  The first core network device may know, by receiving the change message, that the first core network device needs to connect with the terminal device, and the first core network device may perform the change instruction message. By using, the first core network device and the second core network device can be notified to another network element that they are well prepared for the switch to satisfy the demands of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the first core network device receiving an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch. , Comprising steps.

  332. The first core network device sends a release message to a second core network device, where the release message releases a connection between the terminal and the second core network device to the second core network device. Used to instruct

  Based on the release procedure described above, the first core network device can help the second core network device complete the resource release, saving resources.

  A handover method is used by a first access network device, wherein the first access network device receives a handover message, wherein the handover message indicates that a connection between the terminal device and the second access network device includes: Comprising a step used to indicate that a connection between the terminal device and the first access network device needs to be switched. Further, the handover message includes information about an identifier of the terminal device on the second core network interface, wherein the identifier of the terminal device on the second core network interface indicates that the access network device communicates with the second core network device. And the identifier used to identify the terminal device on the interface that performs the

  516. The first access network device generates a report message, wherein the report message indicates that the connection between the terminal device and the second access network device is a connection between the terminal device and the first access network device. Is used to notify the second core network device that it needs to be switched to the second core network device. Further, the report message includes information about the identifier of the terminal device on the second core network interface.

  517. The first access network device sends a report message to the second core network device.

  Optionally, the report message may further include information about a root identifier of the first core network device or information about an identifier of an access network device in the first core network.

  By generating a report message using the handover message, the first access network device may prepare for the switch and send the relevant information to the core network device to satisfy the needs of the network.

  The handover method is used by a first access network device, wherein the access network device receives a change indication message, wherein the change message comprises a connection between the terminal device and the second core network device, A step used to notify the first core network device that it needs to be switched to a connection between the terminal device and the first core network device. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface.

  328. The access network device generates an update message, wherein the change indication message is used to instruct the access network device to instruct the terminal device to perform the update, and optionally, the update message comprises: Used to instruct the terminal device to update the NAS type and / or to update the terminal's key.

  329. The core network device notifies the terminal device of the update message.

  The access network device may know by receiving the change indication message that the second core network device and the first core network device are sufficiently prepared for the switch. The access network device may initiate an update procedure at the terminal side by generating and sending an update message to satisfy the needs of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the access network device transmitting a first message, wherein the first message is information about a root identifier of the first core network device or an access in the first core network. Comprising information about the identifier of the network device.

  By using the first message, the access network device may inform another network element of the information needed in the handover process and prepare well for the handover procedure.

  Further, the handover method further includes the following steps.

  331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

  Further, the handover method further includes the following steps.

  331 '. The access network device sends a release message to the second core network device, wherein the release message instructs the second core network device to release the connection between the terminal and the second core network device. Used to

  Based on the release procedure described above, the first access network device may help the second core network device to complete the resource release, saving resources.

  A handover method is used by the terminal device, the terminal device receiving an update message, wherein the update message is used to instruct the terminal device to perform the update, and optionally, the update message Is used to instruct the terminal device to update the NAS type and / or to update the terminal's key, the steps and the terminal device updating the NAS type and / or updating the terminal's key And a step of performing.

  The terminal may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message, satisfying a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the terminal device transmitting a capability message, wherein the capability message indicates that the terminal device supports that the terminal device establishes a connection with the first core network device. , Which are used for

  The terminal informs another network element that the terminal may support communication with the first core network device by using the capability information, and is fully prepared for the switch.

  A handover method is used by the access network device. The access network device is a second access network device, and the method includes the following steps.

  514. The access network device generates a handover message, wherein the handover message switches a connection between the terminal device and the second access network device to a connection between the terminal device and the first access network device. Used to indicate need. Further, the handover message includes information about the identifier of the terminal device on the second core network interface. The identifier of the terminal device on the second core network interface includes an identifier used to identify the terminal device on the interface with which the access network device communicates with the second core network device, for example, S1 AP UE ID It may be.

  515. An access network device sends a handover message to a first access network device.

  The second access network device sends a handover message, instructing another network element to prepare to establish a connection with the terminal.

  Embodiments of the present invention provide a communication system. The communication system includes a terminal device, a first access network device, a second access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same first access network device. The system may use the handover method shown in FIG. Further, the first core network device and the second core network device may use different core network technologies. For example, the first core network device may be a core network device using an LTE core network technology standard, and the second core network device may be a core network device using a 5G core network technology standard. For another example, the first core network device may be a core network device using the 5G core network technology standard, and the second core network device may be a core network device using the LTE core network technology standard. May be. The first access network device may be compatible with two different core network technologies.

  The following device may relate to the steps of the method described in FIG. Thus, the method steps and related description in FIG. 3 may provide a reference to the following devices and have similar advantages as the following devices. Details will not be described again for brevity. In the following method, it can be understood that the first core network device and the second core network device communicate with the terminal device by using the same first access network device.

  As shown in FIG. 5A, the second core network device 590 is a transceiver unit 5902 configured to receive a report message, wherein the report message comprises a terminal device and a second access network device. Is used to notify the second core network device that the connection between the second core network device and the connection between the terminal device and the first access network device needs to be switched, and the report message further comprises: A transmission / reception unit 5902, including information about an identifier of the terminal device on the second core network interface, and a connection between the terminal device and the second core network device, between the terminal device and the first core network device. Configured to determine that the connection needs to be switched to And a processing unit 5901 to be.

  The transmitting / receiving unit 5902 is further configured to send a change message to the first core network device, wherein the change message is transmitted between the terminal device and the second core network device by the terminal device and the first core network device. Is used to notify the first core network device that the connection to the core network device needs to be switched. Optionally, the change message includes information about the first key of the terminal and / or an identifier of an access network device in the first core network.

  The second core network device determines that a switch is needed, sends a change message, and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, in the second core network device, the terminal device establishes a connection with the second core network device.

  Further, at the second core network device, the transceiver unit is configured to receive the first message, the first message comprising information about a root identifier of the first core network device, or the first core network device. And / or the transmitting / receiving unit is configured to receive a capability message, the capability message indicating that the terminal device establishes a connection with the first core network device. Used to indicate that the terminal device supports it.

  The second core network device knows the information needed in the handover process by using the first message or the capability message and prepares well for the handover procedure.

  Further, at the second core network device, the transceiver unit is configured to receive a release message, wherein the release message releases the connection between the terminal and the second core network device to the second core network device. Used to instruct

  Further, at the second core network device, the processing unit is configured to release a connection between the terminal and the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

  As shown in FIG. 5-2, the first core network device 580 is a transmission / reception unit 5802 configured to receive a change message, wherein the change message comprises a terminal device and a second core network device. Used to notify the first core network device that the connection between the terminal device and the first core network device needs to be switched to a connection between the terminal device and the first core network device; The message is at least one or at least one of contents such as a first key of the terminal, information about an identifier of an access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. A transmitting and receiving unit 5802, including a combination of A processing unit 5801 configured to generate a change indication message, wherein the change indication message is used to instruct an access network device to instruct a terminal device to perform an update, and optionally, The change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is obtained based on the first key. , A processing unit 5801.

  The transmitting / receiving unit 5802 is further configured to send a change indication message to the access network device.

  By receiving the change message, the first core network device knows that the first core network device needs to connect with the terminal device, and the first core network device uses the change instruction message. Thereby, another network element may be notified that the first core network device and the second core network device are well prepared for switching, to satisfy the demands of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, at the first core network device, the transceiver unit is configured to receive an acknowledgment message, wherein the acknowledgment message is for indicating that the access network device and the terminal device have completed the switch. Used, the transceiver unit is configured to send a release message to a second core network device, wherein the release message is transmitted to the second core network device between the terminal and the second core network device. Used to indicate that the connection should be released.

  Based on the release procedure described above, the first core network device can help the second core network device complete the resource release, saving resources.

  As shown in FIG. 5-3, an access network device 570 is provided. The access network device is a first access network device and a transceiver unit 5702 configured to receive the handover message, wherein the handover message indicates that a connection between the terminal device and the second access network device is: The handover message is used to indicate that the connection between the terminal device and the first access network device needs to be switched, and the handover message provides information about the identifier of the terminal device on the second core network interface. And the identifier of the terminal device on the second core network interface is used to identify the terminal device on the interface with which the access network device communicates with the second core network device. A transmitting and receiving unit 5702, including an identifier, and a processing unit 5701 configured to generate a report message, wherein the report message establishes a connection between the terminal device and the second access network device to the terminal device and the second access network device. The second core network interface is used to notify the second core network device that it needs to switch to a connection with the first access network device, and the report message is used to notify the terminal device identifier on the second core network interface. And a processing unit 5701 that includes information about

  The transmitting / receiving unit 5702 is further configured to send the report message to the second core network device.

  Optionally, the report message may further include information about a root identifier of the first core network device, or information about an identifier of an access network device in the first core network.

  By generating a report message using the handover message, the first access network device may prepare for the switch and send the relevant information to the core network device to satisfy the needs of the network.

  The first access network device 570 is a transmitting / receiving unit 5702 configured to receive a change indication message, wherein the change message indicates that a connection between the terminal device and the second core network device is different from the terminal device and the second core network device. Used to notify the first core network device that it needs to switch to a connection with the one core network device, optionally the change indication message comprises a second key of the terminal device; And / or a processing unit 5701 configured to generate an update message, comprising: a transmitting / receiving unit 5702 including information about an identifier of the terminal device on the second core network interface, wherein the change indication message comprises: Update to the terminal device Processing unit 5701 used to instruct to perform, optionally the update message is used to instruct the terminal device to update the NAS type and / or to update the terminal key. And

  The transmitting / receiving unit 5702 is further configured to notify the terminal device of the update message.

  The access network device may know by receiving the change indication message that the second core network device and the first core network device are fully prepared for the switch. The access network device may initiate an update procedure at the terminal side by generating and sending an update message to satisfy the needs of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, at the access network device, the processing unit 3701 is configured to generate a first message, the first message comprising information about a root identifier of the first core network device, or an access at the first core network. Including information about the identifier of the network device, the sending / receiving unit 3702 is configured to send the first message.

  By using the first message, the access network device can inform another network element of the information needed in the handover process and prepare it well for the handover procedure.

  Further, at the access network device, the processing unit 3701 is configured to generate an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch. , The transceiver unit 3702 is configured to send an acknowledgment message to the first core network device.

  Further, at the access network device, the processing unit 3701 is configured to generate a release message, wherein the release message causes the second core network device to establish a connection between the terminal and the second core network device. Used to indicate release, the transceiver unit 3702 is configured to transmit a release message to the second core network device.

  Based on the release procedure described above, the first access network device may help the second core network device to complete the resource release, saving resources.

  As shown in FIG. 5-4, the terminal device is a transmitting / receiving unit 5602 configured to receive the update message, wherein the change indication message causes the access network device to perform the update to the terminal device. The transmit / receive unit 5602, which is used to instruct to instruct, and optionally to instruct the terminal device to update the NAS type and / or to update the terminal key, , Updating the NAS type, and / or updating the terminal key.

  The terminal may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message, satisfying a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, at the terminal device, the processing unit is configured to generate a capability message, wherein the capability message indicates that the terminal device supports that the terminal device establishes a connection with the first core network device. Used for indicating, the transceiver unit is configured to transmit a capability message.

  The terminal informs another network element that the terminal may support communication with the first core network device by using the capability message, and is fully prepared for the switch.

  As shown in FIGS. 5-5, the second access network device 550 is a processing unit 5501 configured to generate a handover message, the handover message comprising a terminal device and a second access network device. Is used to indicate that the connection between the terminal device and the first access network device needs to be switched to the connection between the terminal device and the first access network device; Wherein the identifier of the terminal device on the second core network interface is used to identify the terminal device on the interface with which the access network device communicates with the second core network device. Including, including a processing unit 5501, and configured transceiver unit 5502 to transmit a handover message to the first access network device.

  The terminal may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message, satisfying a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  In the above embodiments, the core network device, the access network device, and the terminal device shown in FIGS. 3 to 5 are collectively referred to as communication devices. The processing units used in these communication devices may be performed by a processor, and the transmitting and receiving units may be performed by a transceiver. A transceiver may also include necessary components such as a transmitter, a receiver, and an antenna. The structure shown in FIG. 6 or FIG. 7 may be used for these communication devices. Details are not described for ease of explanation.

  Although not shown, it can be appreciated that the communication device may further include another device, such as an input device, an output device, and a battery. A processor may include the functionality of operating one or more software programs. The software program may be stored in a memory. The processor, and the software instructions stored in the memory, may typically be configured as operations performed by the communication device. For example, the processor can operate the connection program. The memory may be a read-only memory, a flash memory, or a magnetic storage device, such as a hard disk, a floppy disk drive, or a magnetic tape. The memory may store one or more software programs, instructions, information blocks, data, and the like.

  Optionally, in some embodiments, the memory may separately store the instructions used to perform the method performed by the communication device in the methods illustrated in FIGS. 3-5. The processor may execute the instructions stored in memory and communicate in combination with other hardware (such as a transmitter, a receiver, and an antenna) in the manner shown in FIGS. The steps performed by the device may be completed. For specific work processes and advantageous effects, see the description of the communication device in the embodiment shown in FIGS.

  The steps in the foregoing method can be performed by using hardware integrated logic in a processor or by using instructions in the form of software. The processor may be a general-purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application-specific integrated circuit (Application-Specific Integrated Circuit, ASIC), a field programmable gate array (Field Programmable Gate Array, programmable logic, FPGA logic). It may be a device, a discrete gate or transistor logic device, or a discrete hardware component. A processor may implement or execute the methods, steps, and logical block diagrams disclosed in the embodiments of the present invention. A general purpose processor may be a microprocessor, or the processor may be any conventional processor or the like. The method steps disclosed in connection with embodiments of the present invention may be implemented and implemented directly by using a hardware decoding processor, or by using a combination of hardware and software modules in a decoding processor. And can be realized. The software module may be a random access memory (Random Access Memory, RAM), a flash memory, a read-only memory (Read-Only Memory, ROM), a programmable read-only memory, an electrically erasable programmable memory, or a register. May be located on a mature storage medium. The storage medium is located in the memory, and the processor reads the instructions in the memory and completes the steps in the method described above in combination with the hardware of the processor.

  Those skilled in the art will recognize that each unit and each algorithm step may be implemented by electronic hardware or a combination of computer software and electronic hardware in combination with the examples described in the embodiments disclosed herein. You can recognize what you get. Whether the functions are performed by hardware or software depends upon the particular application of the technical solution and design constraints. Those skilled in the art will be able to perform the described functions by using different methods for each particular application.

  For the sake of brevity and brevity, the detailed operational processes of the aforementioned systems, devices, and units will be referred to the corresponding processes in the foregoing method embodiments, and details will not be described again here. One skilled in the art will understand clearly.

  It should be understood that in some embodiments provided in the present application, the disclosed systems, devices, and methods may be implemented in other manners. For example, the described apparatus embodiment is merely an example. For example, the unit division is merely a logical function division, and may be another division in an actual mounting method. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the illustrated or described mutual couplings or direct couplings or communication connections may be implemented using several interfaces. Indirect coupling or communication connections between devices or units may be implemented in electronic, mechanical, or other forms.

  Units described as separate parts may or may not be physically separated. Also, the portion represented as a unit may or may not be a physical unit, may be located at one location, or may be distributed among multiple network units. Some or all of these units may be selected based on actual requirements to achieve the objectives of the solutions of the embodiments.

  In addition, the functional units in embodiments of the present invention may be integrated into one processing unit, or each of those units may be physically alone, or two or more units may be combined into one unit It may be integrated.

  If the functions are implemented in software functional units and sold or used as a separate product, the functions may be stored on a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, or a part contributing to the prior art, or a part of the technical solution may be realized in the form of a software product. The computer software product is stored on a storage medium and stored on a computer device (which may be a personal computer, a server, or a network device) or a processor, or all of the method steps described in embodiments of the present invention. Includes some instructions to instruct some to execute. The above-described storage medium can store a program code, such as a USB flash drive, a removable hard disk, a read-only memory (ROM, a read-only memory), a random access memory (RAM, a random access memory), a magnetic disk, or an optical disk. Media.

  The preceding description merely identifies embodiments of the present invention and is not intended to limit the protection scope of the present invention. Any modification or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present invention shall fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

  Embodiments of the present invention relate to the field of wireless communication technology, and more specifically, to a handover method, a core network device, an access network device, and a terminal device.

  In a conventional wireless communication network, there is usually an independent network. Correspondingly, each network has a core network device and an access network device corresponding to the network. FIG. 1 shows two independent networks. A 3G network is used as an example. The core network device of the 3G network may be a serving GPRS support node (SGSN) and the access network device of the 3G network may be a radio network controller (RNC). For a 4G network, the access network device of the 4G network may be an eNB, and the core network device of the 4G network may be a mobility management entity (MME) or a PDN gateway (P-GW) / gateway GPRS support node (GGSN). ). When a terminal device is handed over from one network to another, for example, when a terminal device is handed over from a 3G network to a 4G network, the access network device and the core network device of the two networks need to be scheduled. Specifically, the following procedure or a similar procedure may be included. The RNC determines the target cell that needs to perform the handover based on the UE measurement, selects the target eNB based on the target cell, and sends a handover request to the SGSN. SGSN forwards the handover message to MME. The MME establishes a connection between the S-GW / P-GW and the eNB in the LTE network. After establishing a connection with the target eNB, the MME informs the SGSN of the radio connection bearer (RAB) that has been successfully established, and the SGSN communicates with the failed RAB that needs to be released and the data transfer. Responsible for notifying the RNC of the required, successfully established RAB.

  With the development of wireless communication technology, when the network structure changes, the existing solutions cannot solve the problem of switching the connection between the terminal device and the core network device.

  Embodiments of the present invention provide a handover method, a core network device, an access network device, and a terminal device to provide a more effective handover solution when the network structure changes.

  According to one aspect, embodiments of the present invention provide a handover method. The method is applied to the communication system shown in FIG. The communication system includes a terminal device, an access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device.

  The method comprises the following steps.

  Optionally, 311. The terminal device establishes a connection with the second core network device.

Optionally, 312. An access network device sends a first message to a second core network device, where the first message includes information about a root identifier of the first core network device or access in the first core network. Contains information about the identifier of the network device. The information about the route identifier of the first core network device is used to indicate a route of a message to be transmitted by the second core network device to the first core network device.

  Optionally, 313. The second core network device receives the capability message, where the capability message is used to indicate that the terminal device supports establishing a connection with the first core network device. .

321. The second core network device determines that the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. Further, the second core network device may determine that a switch is needed based on the conditions of the second core network device. For example, no more services can be accepted based on the load status of the second core network device . For example, the condition has exceeded a threshold. For example, the number of terminal devices currently accessing the second core network has exceeded a certain threshold. Alternatively, the switch may be triggered based on an event, for example, an event that a message sent by another network element is received. Alternatively, the switching may be triggered based on the service information of the terminal device, for example, based on the characteristics of the service currently being requested by the user of the terminal device, the terminal device may be configured to execute in the first core network. Suitable, can trigger switching.

323. The second core network device sends a change message to the first core network device, wherein the change message indicates that a connection between the terminal device and the second core network device is a connection between the terminal device and the first core network device. Used to notify the first core network device that it needs to switch to a connection with the device. Optionally, the change message has content such as a first key of the terminal device , information about an identifier of the access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof. Since the second core network device has established a connection with the terminal device, the second core network device has the stored first key of the terminal device. The second core network device may obtain a route for sending a change message to the first core network device based on the information about the route identifier of the first core network device . Further, the second core network device sends the change message after generating the message.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct the access network device to instruct the terminal device to perform the update. Optionally, the change indication message includes information about the second key of the terminal device and / or the terminal device n identifier on the second core network interface, wherein the second key is associated with the first key. Obtained based on The identifier of the terminal device on the second core network interface includes an identifier used to identify the terminal device on the interface with which the access network device communicates with the second core network device, for example, S1 AP UE ID Can be Typically, the S1 AP UE ID includes a pair of UE identifiers. For example, the S1 AP UE ID further includes an eNB S1 AP UE ID and / or an MME S1 AP UE ID. The eNB S1 AP UE ID is an identifier used to identify a base station UE on the S1 interface, and the MME S1 AP UE ID is an identifier used to identify the MME UE on the S1 interface. It is. Similarly, the identifier may alternatively be an NG1 AP UE ID, and the identifier NG1 AP UE ID includes gNB NG1 AP UE ID and / or NG-C NG1 AP UE ID.

After receiving the change message, the first core network device may know that the first core network device is going to accept the task of establishing a connection with the terminal device, and correspondingly, The core network device prepares resources and prepares to establish communication with the terminal device. If the first core network device determines that the first core network device cannot accept the task, the first core network device may feed back a rejection message to the second core network device (not shown). ), And the second core network device may search for another core network device or another processing method based on the rejection message (not shown).

The first key is a key used for communication between the terminal device and the second core network device and adapted to the second core network technology. The first core network device, by using the core network technology of the first core network device, based on a first key of the terminal device, the second key being adapted terminal devices in the first core network presume. Correspondingly, the second key is a key used for communication between the terminal device and the first core network device and adapted to the first core network technology.

  327. The first core network device sends a change indication message to the access network device. Further, the first core network device may send a change indication message to the access network device based on the information about the identifier of the access network device in the first core network.

328. The access network device generates an update message, where the update message is used to instruct the terminal device to perform an update, and optionally, the update message indicates to the terminal device the NAS type. Used to update and / or to update the key of the terminal device . Updated key of the terminal device is obtained based on the local key that is stored on the terminal device. Optionally, a new key is estimated from the local key by using the same estimation method as the first core network device. The NAS of the terminal device is a function of communication between the terminal device and the core network device, and different types of NAS need to be used between the terminal device and the different types of core network devices. For example, the NAS function defined in the 3G protocol needs to be used for communication between the terminal device and the 3G core network device, and the NAS function defined in the 4G protocol is a terminal device. And the NAS function defined in the 5G protocol is used for communication between the terminal device and the 5G core network device. There is a need.

329. The access network device notifies the terminal device of the update message.

  341. The terminal device updates the local key and / or changes the non-access layer NAS type based on the update message.

  Optionally, 331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

Optionally, 332. The first core network device sends a release message to a second core network device, wherein the release message informs the second core network device of a connection between the terminal device and the second core network device. Used to indicate that the

The method may further comprise, as an alternative to steps 331 and 332, step 331 ′: the access network device sends a release message to the second core network device, and the release message is transmitted to the second core network device. , For instructing to release the connection between the terminal device and the second core network device.

Optionally, the second core network device releases a connection between the terminal device and the second core network device (not shown).

Based on the handover procedure initiated by the second core network device , the connection between the terminal device and the second core network device can be switched between the terminal device and the first core network device without switching the access network device. Connection can be switched, thereby efficiently fulfilling network communication requirements.

Further, in the network communication processing, the terminal device updates the key of the terminal device and the used communication protocol in a timely manner, and completes the switching without any problem.

  A communication system, a second core network device, a first core network device, an access network device, and a terminal device using the foregoing method are disclosed separately and have similar advantages. See FIG. 3, FIG. 3-1, FIG. 3-2, FIG. 3-3, and FIG. 3-4.

  According to another aspect, embodiments of the present invention provide a handover method. The method is applied to the communication system shown in FIG. The communication system includes a terminal device, an access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device.

  The method comprises the following steps.

Optionally, 311. The terminal device establishes a connection with the second core network device by using the access network device.

  Optionally, 312. An access network device sends a first message to a second core network device, where the first message includes information about a root identifier of the first core network device or access in the first core network. Contains information about the identifier of the network device.

421. The access network device determines that the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. Further, the access network device may initiate the switch based on conditions of the access network or a state of the second core network device. For example, the access network device infers that it can no longer accept services based on the load status of the second core network device. Alternatively, the access network device receives the message of the second core network device and is informed that a switch is needed, in which case the access network device actively determines that a switch is needed decide. It can be appreciated that the access network device may alternatively receive a message sent by another network element to trigger the switch.

422. The access network device sends a change message to the second core network device, wherein the change message indicates that the connection between the terminal device and the second core network device is between the terminal device and the first core network device. Is used to notify the second core network device that it needs to be switched to a connection between. Optionally, the change message includes information about an identifier of the terminal device on the second core network interface. The identifier of the terminal device on the second core network interface is an identifier used by the access network device to identify the terminal device on the interface that communicates with the second core network device.

  Optionally, the change message may include information about a root identifier of the first core network device and / or information about an identifier of an access network device in the first core network. It can be seen that two types of information are used by the second core network device. If the second core network device learns the information or a part of the information in another way, it is not necessary to transmit the known information using step 312 or step 422. It is understood that one or both of information about the root identifier of the first core network device and information about the identifier of the access network device in the first core network may be sent by using the first message in step 312. Can be done. In this case, the change message in step 422 may not include the information sent by using the first message. Alternatively, one or both of the information about the root identifier of the first core network device and the information about the identifier of the access network device in the first core network may be sent by using the change message in step 422. In this case, the first message in step 312 may not include the information that needs to be sent by using the change message, or even step 312 may be omitted.

  423. The second core network device generates a change acknowledgment message, wherein the change acknowledgment message indicates that the connection between the terminal device and the second core network device is between the terminal device and the first core network device. Is used to notify the first core network device that it needs to be switched to a connection between them. Optionally, the change acknowledgment message includes a first key of the terminal device, information about an identifier of the access network device in the first core network, information about an identifier of the terminal device on the second core network interface, and the like. Includes one or a combination of the three items. The second core network device receives the change message, and the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. And prepare communication resources accordingly. To enable the first core network device to connect with the terminal device without any problems, the second core network device sends corresponding information. The first key of the terminal device, the information about the identifier of the access network device in the first core network, and the information about the identifier of the terminal device on the second core network interface are the same as those in the solution of FIG. Or match. Details will not be described again.

  424. The second core network device sends a change acknowledgment message to the first core network device.

  Optionally, the second core network device may discover the first core network device based on information about a root identifier of the first core network device.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct the access network device to instruct the terminal device to perform the update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is the first key Obtained based on

  327. The first core network device sends a change indication message to the access network device.

328. The access network device generates an update message, wherein the update message is used to instruct the terminal device to perform the update, and optionally, the update message indicates to the terminal device the NAS type. Used to update and / or to update the key of the terminal device . Updated key of the terminal device is obtained based on the local key that is stored on the terminal device.

329. The access network device notifies the terminal device of the update message.

341. The terminal device updates the local key and / or changes the non-access layer NAS type based on the update message. Updating the NAS type includes updating the NAS type used to communicate with the second core network device to the NAS type used to communicate with the first core network device , Updating the device key updates the first key used to communicate with the second core network device to a second key used to communicate with the first core network device. Including.

  Optionally, 331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

Optionally, 332. The first core network device sends a release message to a second core network device, wherein the release message informs the second core network device of a connection between the terminal device and the second core network device. Used to indicate that the

The method may further comprise, as an alternative to steps 331 and 332, a step 331 ′: the access network device sends a release message to the second core network device, wherein the release message is transmitted to the second core network device. Used to instruct the device to release the connection between the terminal device and the second core network device.

Further, the second core network device releases the connection between the terminal device and the second core network device (not shown).

Based on the handover procedure is initiated by the access network device, a connection between the terminal device and a second core network device without switching the access network device, a connection between the terminal device and the first core network device , Thereby efficiently fulfilling network communication requirements.

  A communication system, a second core network device, a first core network device, an access network device, and a terminal device using the foregoing method are disclosed separately and have similar advantages. See FIGS. 4, 4-1, 4-2, 4-3, and 4-4.

  According to yet another aspect, an embodiment of the present invention provides a handover method. The method is applied to the communication system shown in FIG. The communication system includes a terminal device, a first access network device, a second access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device, and the same access network device is the first access network device.

  The method comprises the following steps.

  Optionally, 311. The terminal device establishes a connection with the second core network device by using the second access network device.

  Optionally, 312. A first access network device sends a first message to a second core network device, where the first message includes information about a root identifier of the first core network device, or a first core network device. Contains information about the identifier of the access network device in the network.

  Optionally, 313. The second core network device receives the capability message, where the capability message is used to indicate that the terminal device supports establishing a connection with the first core network device. .

  514. The second access network device generates a handover message, wherein the handover message indicates that a connection between the terminal device and the second access network device is a connection between the terminal device and the first access network device. Used to indicate that it needs to be switched to. Further, the handover message includes information about the identifier of the terminal device on the second core network interface. The identifier of the terminal device on the second core network interface includes an identifier used to identify the terminal device on the interface with which the access network device communicates with the second core network device, for example, S1 AP UE ID It may be.

  515. The second access network device sends a handover message to the first access network device.

The second access network device sends a handover message, instructing another network element to prepare to establish a connection with the terminal device .

516. The first access network device generates a report message, wherein the report message indicates that the connection between the terminal device and the second access network device is a connection between the terminal device and the first access network device. Is used to notify the second core network device that it needs to be switched to the second core network device. Further, the report message includes information about the identifier of the terminal device on the second core network interface. As with the change message in another aspect , the report message may further include information about a root identifier of the first core network device, or information about an identifier of an access network device in the first core network.

  517. The first access network device sends a report message to the second core network device.

  521. The second core network device determines that the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device.

523. The second core network device sends a change message to the first core network device, wherein the change message indicates that a connection between the terminal device and the second core network device is between the terminal device and the first core network device. It is used to notify the first core network device that it needs to switch to a connection with the network device. Optionally, the change message has content such as a first key of the terminal device , information about an identifier of the access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct the terminal device to instruct the access network device to perform the update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is the first key Obtained based on

  327. The first core network device sends a change indication message to the first access network device. Further, the first core network device may send a change indication message to the access network device based on the information about the identifier of the access network device in the first core network.

328. The first access network device generates an update message, wherein the update message is used to instruct the terminal device to perform an update, and optionally, the update message is transmitted to the terminal device by the NAS. Used to update the type and / or to update the key of the terminal device . Updated key of the terminal device is obtained based on the local key that is stored on the terminal device.

  529. The first access network device notifies the terminal device of the update message.

  If the first access network device has completed the inter-cell handover from the second access network device, in other words, if the first access network device has established a direct connection with the terminal device, the second access network is no longer available. It can be appreciated that the device need not be used and the first access network device may notify the terminal device of the update message directly. As an alternative solution, the first access network device may forward the update message using the second access network device (not shown), in other words, the second access network device sends the update message It can be seen that only the transfer of the update message is performed without processing.

Optionally, the method may further comprise the first access network device sending a message to the second access network device (not shown), wherein the message is switched to the second access network device. Has been completed and is used to indicate that the connection with the terminal device may be released. The message may be sent before or after the update message, and a similar function may instead be completed by using the information held in the update message.

  341. The terminal device updates the local key and / or changes the non-access layer NAS type based on the update message. See the solution in FIG.

  Optionally, 331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

Optionally, 332. The first core network device sends a release message to a second core network device, wherein the release message informs the second core network device of a connection between the terminal device and the second core network device. Used to indicate that the

The method may further comprise, as an alternative to steps 331 and 332, a step 331 ′: the access network device sends a release message to the second core network device, wherein the release message is transmitted to the second core network device. Used to instruct the device to release the connection between the terminal device and the second core network device.

  Optionally, the second core network device releases a connection between the terminal and the second core network device (not shown).

Based on the handover procedure initiated by the second core network device , the connection between the terminal device and the second core network device can be switched between the terminal device and the first core network device without switching the access network device. Connection can be switched, thereby efficiently fulfilling network communication requirements.

  Initially, only conventional inter-cell handover is started for the terminal device. Specifically, a handover from the second access network device to the first access network device is performed. However, since the first access network device accesses the first core network device in addition to the access to the second core network device, the second core network device is further based on a conventional inter-cell handover. , Trigger a handover from the second core network device to the first core network device, thereby providing different qualities of service. For example, the UE originally performs inter-cell handover only in the 5G network. Since the target base station is an e-eNB and the base station can also access the 4G network, the 5G core network device further hands over the UE to the 4G network, and the corresponding core network device is also a 4G EPC. In the early stages of establishing a 5G network, the UE can be more quickly handed over to the 4G network by using the above solution due to the lack of 5G service capability, which allows the handover request Is satisfied.

  A communication system, a second core network device, a first core network device, a first access network device, a terminal device, and a second access network device using the foregoing method are separately disclosed and have similar advantages. . See FIG. 5, FIG. 5-1, FIG. 5-2, FIG. 5-3, FIG. 5-4, and FIG. 5-5.

  According to yet another aspect, embodiments of the present invention provide a computer-readable storage medium, wherein the computer-readable storage medium stores instructions used to perform a method used by the aforementioned communication device. However, the instructions include a program designed to perform the above aspects. The communication device may be a core network device, an access network device, or a terminal device.

  According to yet another aspect, an embodiment of the invention provides a communication device, wherein the communication device comprises a memory and a processor, wherein the memory comprises the computer readable storage medium in the preceding aspect, wherein the processor comprises: , Used to perform the method used by the communication device, and configured to execute instructions stored on the computer-readable storage medium. The communication device may be a core network device, an access network device, or a terminal device.

  According to yet another aspect, an embodiment of the present invention provides a communication system, wherein the system comprises the core network device, the access network device, and the terminal device in the aforementioned aspect.

  According to the technical solution provided in the embodiment of the present invention, a new handover solution may be provided. In the system, the first core network device and the second core network device communicate with the terminal device by using the same access network device.

FIG. 2 is a schematic diagram of two existing communication systems.

1 is a schematic diagram of a communication system according to an embodiment of the present invention.

4 is a schematic flowchart of a handover method according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a second core network device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a first core network device according to an embodiment of the present invention.

1 is a schematic diagram of an access network device according to an embodiment of the present invention.

It is a schematic diagram of a terminal device concerning an embodiment of the present invention.

4 is a schematic flowchart of a handover method according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a second core network device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a first core network device according to an embodiment of the present invention.

1 is a schematic diagram of an access network device according to an embodiment of the present invention.

It is a schematic diagram of a terminal device concerning an embodiment of the present invention.

4 is a schematic flowchart of a handover method according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a second core network device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a first core network device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a first access network device according to an embodiment of the present invention.

It is a schematic diagram of a terminal device concerning an embodiment of the present invention.

FIG. 3 is a schematic diagram of a second access network device according to an embodiment of the present invention.

1 is a schematic diagram of a communication device according to an embodiment of the present invention.

1 is a schematic diagram of a communication device according to an embodiment of the present invention.

  The embodiment of the present invention provides a solution based on the communication system shown in FIG. As shown in FIG. 2, an embodiment of the present invention provides a communication system. The communication system comprises an access network device 203 (such as an e-eNB), a first core network device 201 (such as an EPC), and a second core network device 202 (such as a NextGen core). The corresponding interface may be an S1 interface or an NG1 interface.

The technical solutions in the embodiments of the present invention include, for example, code division multiple access ( CDMA) system, time division multiple access ( TDMA) system, frequency multiple access ( FDMA) system, orthogonal frequency division multiple access for data processing. It can be applied to various communication systems such as connection ( OFDMA) systems, single carrier frequency multiple access ( SC-FDMA) systems, and other systems. The terms "system" and "network" are interchangeable. Radio technologies such as Universal Terrestrial Radio Access ( UTRA) and CDMA2000 may be implemented in CDMA systems. UTRA may include wideband CDMA ( WCDMA®) technology, and another technology converted from CDMA. CDMA2000 may cover the Interim Standard ( IS) 2000 (IS-2000), the IS-95 Standard, and the IS-856 Standard. Wireless technologies such as Global System for Mobile Communications ( GSM) may be implemented in TDMA systems. Wireless technologies such as Evolved Universal Terrestrial Radio Access ( E-UTRA), Ultra Mobile Broadband ( UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMax), IEEE 802.20, and flash OFDMA are OFDMA systems. Can be performed. UTRA corresponds to UMT, and E-UTRA corresponds to an evolved version of UMT. A new version of UMT, E-UTRA, is used in 3GPP Long Term Evolution ( LTE) and various versions that have evolved based on LTE. Fifth generation ( 5G) communication systems and New Radio ( NR) are the next generation communication systems under study. In addition, the communication system 200 is further applicable to future communication technologies to which the technical solutions provided in the embodiments of the present invention can be applied. The system architecture and service scenarios described in the embodiments of the present invention are intended to more clearly describe the technical solutions in the embodiments of the present invention, but are provided in the embodiments of the present invention. It is not intended to limit the technical solutions. Those skilled in the art may know that as the network architecture evolves and new service scenarios emerge, the technical solutions provided in the embodiments of the present invention are further applicable to similar technical problems.

A terminal device, also referred to as user equipment ( UE), mobile terminal ( MT), mobile user equipment, or the like, may include one or more core networks via a radio access network (eg, a Radio Access Network, RAN). Can communicate with The user equipment may be a mobile phone (or referred to as a "cellular" phone) or a mobile terminal device such as a computer with a mobile terminal. For example, the user equipment may be portable, pocket-sized, handheld, self-contained, or on-board mobile.

The access network device may be an apparatus arranged in a wireless access network for providing a terminal device with a wireless communication function. Access network devices may include macro base stations, micro base stations (also referred to as small cells), relay nodes, access points, and the like in various forms, and various forms of control nodes such as network controllers. May also be included. A control node may be connected to multiple base stations and configure resources for multiple terminal devices included in the coverage of multiple base stations. In a system using different wireless access technologies, devices having the function of an access network device may have different names, for example, may correspond to base stations and base station controllers in 2G, or may correspond to base stations and base stations in 3G. An eNB or eNodeB in RNC or LTE, or a base station in 5G (currently no formal name exists, eg G-NB or NX-NB) or NR, or a transmit / receive point ( TRP) Good. This is not limited in the present invention.

The core network device may be a device used in the network after the access network device, typically connected to the access network device, based on the function, a plurality of core network devices may exist. In a system using different wireless connection technologies, devices having the function of the core network device may have different names, for example, corresponding to MME or S-GW in LTE, or corresponding to SGSN / GGSN in 3G. Often, there is no official name in 5G such as NG-Core.

  [First Embodiment]

  Embodiments of the present invention provide a handover method. The method is applied to the communication system shown in FIG. The communication system includes a terminal device, an access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device. Further, the first core network device and the second core network device may use different core network technologies. For example, the first core network device may use LTE core network technology and the second core network device may use 5G core network technology. For another example, the first core network device may use 5G core network technology and the second core network device may use LTE core network technology.

  As shown in FIG. 3, the method comprises the following steps.

  311. A terminal device establishes a connection with the second core network device. The terminal device may establish a connection with the second core network device in a known manner. Typically, the terminal device establishes a connection with the second core network device by using the access network device. However, those skilled in the art will appreciate that the connection may be established in another manner. For example, the terminal device sends the message directly to the second core network device.

312. The access network device sends a first message to a second core network device, where the first message includes information about a root identifier of the first core network device or access in the first core network. Contains information about the identifier of the network device. Information about the route identifier of the first core network device is used to indicate a second core network device by the first route message will be sent to the core network device. For example, the information on the route identifier of the first core network device may be information including the tracking area code TAC. The information about the identifier of the access network device in the first core network may be information about the identifier of the access network device when the access network device communicates with the first core network device. It can be appreciated that the information about the identifier may be an identifier, or may be an index or other information. The information about the root identifier of the first core network device and the information about the identifier of the access network device in the first core network are information that can be used by the second core network device, and are not necessarily the first message. It should be noted that it need not be sent by using. The first message may be known to the second core network device when the second core network device may obtain one of the two pieces of information in another manner, eg, by agreement. It can be appreciated that the information may not be included. Of course, the first message may instead include information about the root identifier of the first core network device and information about the identifier of the access network device in the first core network. Since the first core network device and the second core network device communicate with the terminal device by using the same access network device, the access network device is related to the first core network device, ie, the first core network device. It can be appreciated that knowing the information that can be included in the message.

313. The second core network device receives the capability message, where the capability message is used to indicate that the terminal device supports establishing a connection with the first core network device. . It can be appreciated that the capability message may be sent by the terminal device to the second core network device or may be sent by the access network device to the second core network device. For example, capability message may be a non-access stratum NAS message.

321. The second core network device determines that the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. Further, the second core network device may determine that a switch is needed based on the conditions of the second core network device. For example, no more services can be accepted based on the load status of the second core network device . For example, the condition has exceeded a threshold. Alternatively, the switch may be triggered based on an event, for example, an event that a message sent by another network element is received.

323. The second core network device sends a change message to the first core network device, wherein the change message indicates that a connection between the terminal device and the second core network device is between the terminal device and the first core network device. Used to notify the first core network device that it needs to be switched to a connection with the core network device. Optionally, the change message has content such as a first key of the terminal device , information about an identifier of the access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof. Since the second core network device has established a connection with the terminal device, the second core network device has stored the first key of the terminal device. Second core network device, based on information about the route identifier of the first core network device may obtain a route for transmitting the change message to the first core network device. Further, the second core network device sends the change message after generating the message. Information about the terminal device identifier on the second core network interface may be used to indicate which terminal device needs to be processed. The identifier of the terminal device on the second core network interface includes an identifier used to identify the terminal device on the interface with which the access network device communicates with the second core network device, for example, S1 AP UE ID It may be.

The second core network device may notify another network element that a switch is needed by using the change message and trigger a subsequent procedure.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct an access network device to instruct a terminal device to perform an update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is based on the first key. Is obtained.

After receiving the change message, the first core network device may know that the first core network device is going to accept the task of establishing a connection with the terminal device, and accordingly, responds to the first core network device. The core network device prepares resources and prepares to establish communication with the terminal device. If the first core network device determines that the first core network device cannot accept the task, the first core network device may feed back a rejection message to the second core network device (not shown). ) And the second core network device searches for another core network device or another processing method based on the rejection message (not shown).

The first key is a key used for communication between the terminal device and the second core network device and adapted to the second core network technology. The first core network device, by using the core network technology of the first core network device, based on a first key of the terminal device, the second key being adapted terminal devices in the first core network presume.

  327. The first core network device sends a change instruction message to the access network device. Further, the first core network device may send a change indication message to the access network device based on the information about the identifier of the access network device in the first core network.

328. The access network device generates an update message, where the update message is used to instruct the terminal device to perform an update, and optionally, the update message indicates to the terminal device the NAS type. Used to update and / or update the terminal device key. Updated key of the terminal device, based on the local key that is stored on the terminal device, is obtained. Optionally, the new key is estimated from the local key by using the same estimation method as that of the first core network device.

  The access network device may know the terminal device whose key needs to be updated based on the information about the identifier of the terminal device on the second core network interface. When communicating with the terminal device, the access network device receives the second key and stores it locally, like using the second key.

329. The access network device notifies the terminal device of the update message.

341. The terminal device updates the local key and / or changes the non-access layer NAS type based on the update message. Updating the NAS type includes updating the NAS type used to communicate with the second core network device to the NAS type used to communicate with the first core network device , Updating the device key updates the first key used to communicate with the second core network device to a second key used to communicate with the first core network device. Including. Further, the local key of the terminal device is used to communicate with the second core network device, and the key now needs to be updated. Specifically, there is a mapping relationship between the local key of the terminal device and the first key of the terminal device on the second core network device. The mapping relationship may be such that the first key is the same as the second key, or the first key may be obtained by an operation. Since the first core network device has updated the first key on the network side with a second key that satisfies the request of the first core network device, the terminal device needs to obtain a new key in the corresponding estimation scheme. This satisfies the request for communicating with the first core network device. Correspondingly, instead of satisfying the request to communicate with the second core network device, the original NAS type also needs to be updated to satisfy the request to communicate with the first core network device. For example, a 5G NAS type is updated to a 4G NAS type.

  331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

332. The first core network device sends a release message to a second core network device, wherein the release message establishes a connection between the terminal device and the second core network device to the second core network device. Used to indicate release.

The method may further include, as an alternative to steps 331 and 332, step 331 ': the access network device sends a release message to the second core network device, wherein the release message is transmitted to the second core network device. To release the connection between the terminal device and the second core network device.

  Further, the second core network device releases the connection between the terminal and the second core network device (not shown).

Based on the handover procedure initiated by the second core network device , the connection between the terminal device and the second core network device can be switched between the terminal device and the first core network device without switching the access network device. Connection can be switched, thereby efficiently fulfilling network communication requirements.

Further, in the network communication processing, the terminal device updates the key of the terminal device and the communication protocol to be used in a timely manner, and completes the switching without any problem.

In the flowchart of FIG. 3, the dashed lines indicate that the steps are optional. Specifically, one of steps 311, 312, 313 and 313 'or a combination thereof may be omitted, and one of steps 331, 332 and 331' or a combination thereof may be omitted. Specifically, when the second core network device knows information about the root identifier of the first core network device or information about the identifier of the access network device in the first core network, step 312 is omitted. In other words, the first message need not be sent. When the second core network device knows that the terminal device supports that the terminal device establishes a connection with the first core network device, steps 313 and 313 ′ may be omitted, in other words, No capability information needs to be sent. When the second core network device has a suitable mechanism, such as, for example, a timeout mechanism, the steps 331, 332 and 331 'are performed so as to release the connection between the terminal device and the second core network device. May be omitted, in other words, the release message does not need to be sent to release resources. It can be seen that omitting the foregoing steps does not affect the technical effect of the solution of FIG. 3 and does not affect the function of the various network elements.

  The following different methods can be obtained for the various network elements of FIG. The following method is consistent with the method of FIG. 3 and the same parts will not be described again in detail. The steps of the method of FIG. 3 and the associated description may provide a reference to the following method and have similar advantages as the following method. Details will not be described again for brevity. In the following method, it can be understood that the first core network device and the second core network device communicate with the terminal device by using the same access network device.

  The handover method is used by the second core network device and includes the following steps.

  321. The second core network device determines that the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device.

323. The second core network device sends a change message to the first core network device, wherein the change message indicates that a connection between the terminal device and the second core network device is between the terminal device and the first core network device. It is used to notify the first core network device that it needs to switch to a connection with the network device. Optionally, the change message has content such as a first key of the terminal device , information about an identifier of the access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof.

  The second core network device determines that a switch is needed, sends a change message, and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the following steps: 311. The terminal device establishes a connection with the second core network device.

  Further, the handover method further comprises the step of the second core network device receiving the first message, wherein the first message includes information about the root identifier of the first core network device, or the first message. And / or wherein the second core network device receives the capability message including information about an identifier of the access network device in the core network, wherein the capability message indicates that the terminal device has the first core. Used to indicate that the terminal device supports establishing a connection with the network device.

The second core network device knows the information needed in the handover procedure by using the first message or the capability message and prepares well for the handover procedure.

Furthermore, the handover method further comprises the step of the second core network device receiving a release message, wherein the release message informs the second core network device of the connection between the terminal device and the second core network device. Used to instruct the user to release.

Further, the handover method further comprises the second core network device releasing the connection between the terminal device and the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

The handover method is used by a first core network device , the first core network device receiving a change message, wherein the change message is transmitted to the first core network device by the terminal device and the second core network. Used to signal that the connection between the device and the terminal device and the first core network device needs to be switched. Optionally, the change message has content such as a first key of the terminal device , information about an identifier of the access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct an access network device to instruct a terminal device to perform an update. The change indication message may include information about the second key of the terminal device and / or the identifier of the terminal device on the second core network interface, wherein the second key is obtained based on the first key. Is done.

  327. The first core network device sends a change instruction message to the access network device.

  By receiving the change message, the first core network device may know that the first core network device needs to connect to the terminal device, and the first core network device sends the change instruction message to the terminal device. By using it, it may be known that the first core network device and the second core network device may inform another network element that the first core network device and the second core network device are sufficiently prepared for switching. . In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the first core network device receiving an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch. It has a stage.

332. The first core network device sends a release message to a second core network device, wherein the release message informs the second core network device of a connection between the terminal device and the second core network device. Used to indicate that the

  Based on the release procedure described above, the first core network device can help the second core network device complete the resource release, saving resources.

  A handover method is used by the access network device, wherein the access network device receives a change indication message, the change indication message instructing the access network device to instruct the terminal device to perform the update. , Which is used for Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface.

328. The access network device generates an update message, where the update message is used to instruct the terminal device to perform the update. Optionally, the update message is used to instruct the terminal device to update the NAS type and / or to update the terminal device 's key.

329. The access network device notifies the terminal device of the update message.

  The access network device may know by receiving the change indication message that the second core network device and the first core network device are well prepared for the switch. The access network device may initiate an update procedure at the terminal side by generating and transmitting an update message to satisfy the requirements of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the access network device transmitting a first message, wherein the first message is information about a root identifier of the first core network device or in the first core network. Comprising information about an identifier of the access network device.

By using the first message, the access network device may inform another network element of the information required in the handover procedure , and prepare sufficiently for the handover procedure.

  Further, the handover method further includes the following steps.

  331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

  Further, the handover method further includes the following steps.

331 '. The access network device sends a release message to the second core network device, where the release message releases the connection between the terminal device and the second core network device to the second core network device. Used to indicate

Based on the aforementioned release procedure, access network device, the second core network devices to obtain help to complete the resource release, to conserve resources.

A handover method is used by the terminal device, the terminal device receiving an update message, wherein the update message is used to instruct the terminal device to perform an update, and optionally, the update message Steps used to instruct the terminal device to update the NAS type and / or to update the terminal device 's key, and the steps wherein the terminal device updates the NAS type and / or updates the terminal's key And a step of performing.

NAS type update step includes the step of updating the NAS type used for communicating with the second core network device, the NAS type used for communicating with the first core network device, a terminal device Updating the key of the first step is a step of updating a first key used for communicating with the second core network device to a second key used for communicating with the first core network device. including.

The terminal device may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message, satisfying a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the terminal device transmitting a capability message, wherein the capability message indicates that the terminal device supports that the terminal device establishes a connection with the first core network device. , Which are used for

The terminal device informs another network element that the terminal device may support communication with the first core network device by using the capability information to fully prepare for the switch.

  Embodiments of the present invention provide a communication system. The communication system includes a terminal device, an access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device. The system may use the handover method shown in FIG. Further, the first core network device and the second core network device may use different core network technologies. For example, the first core network device may be a core network device using an LTE core network technology standard, and the second core network device may be a core network device using a 5G core network technology standard.

The following devices may relate to the steps of the method described in FIG. Thus, the method steps and related description in FIG. 3 may provide a reference to the following devices and have similar advantages. Details will not be described again for brevity. In the following embodiments , it can be understood that the first core network device and the second core network device communicate with the terminal device by using the same access network device.

  As shown in FIG. 3A, the second core network device 390 is configured such that a connection between the terminal device and the second core network device is a connection between the terminal device and the first core network device. A processing unit 3901 configured to determine that the first core network device and the second core network device communicate with a terminal device by using the same access network device. A unit 3901 and a transceiver unit 3902 configured to send a change message to a first core network device, the change message comprising: a connection between the terminal device and the second core network device; Between the first core network device That need to be switched to the connection used to notify the first core network device, and a transmitting and receiving unit 3902.

Optionally, the change message has content such as a first key of the terminal device , information about an identifier of the access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof.

  The second core network device determines that a switch is needed, sends a change message, and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, in the second core network device, the terminal device establishes a connection with the second core network device.

  Further, at the second core network device, the transmitting / receiving unit is configured to receive the first message, wherein the first message includes information about a root identifier of the first core network device, or The information includes information about an identifier of an access network device in one of the core networks, and / or the transmitting / receiving unit is configured to receive the capability message, wherein the capability message indicates that the terminal device is in communication with the first core network device. Is used to indicate that the terminal device supports establishing a connection.

The second core network device may know the information needed in the handover procedure by using the first message or the capability message to fully prepare for the handover procedure .

Further, at the second core network device, the transceiver unit is configured to receive a release message, wherein the release message is transmitted to the second core network device between the terminal device and the second core network device. Used to indicate that the connection should be released.

Further, at the second core network device, the processing unit is configured to release a connection between the terminal device and the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

As shown in FIG. 3-2, the first core network device 380 is a transmission / reception unit 3802 configured to receive a change message, wherein the change message comprises a terminal device and a second core network device. The first core network device is used to notify the first core network device that the connection between the first core network device and the first core network device needs to be switched to a connection between the terminal device and the first core network device. And the second core network device communicates with the terminal device by using the same access network device, and optionally, the change message includes a first key of the terminal device , an access network device in the first core network. About the identifier of the second core A transmission / reception unit 3802 including at least one or a combination thereof, such as information on an identifier of a terminal device on a network interface, and a processing unit 3801 configured to generate a change instruction message, the change instruction comprising: The message is used to instruct the access network device to instruct the terminal device to perform an update, and optionally, the change instruction message includes a second key of the terminal device and / or a second core. The second key includes information about the identifier of the terminal device on the network interface, and the processing unit 3801 is obtained based on the first key.

  The transmitting / receiving unit 3802 is further configured to send a change indication message to the access network device.

  The first core network device may know by receiving the change message that the first core network device needs to connect to the terminal device, and the first core network device By using the change indication message to satisfy the request, another network element may be notified that the first core network device and the second core network device are fully prepared for the switch. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

Further, at the first core network device, the transceiver unit is configured to receive an acknowledgment message, wherein the acknowledgment message is for indicating that the access network device and the terminal device have completed the switch. Used. The transceiver unit is configured to send a release message to the second core network device, where the release message causes the second core network device to establish a connection between the terminal device and the second core network device. Used to indicate release.

  Based on the release procedure described above, the first core network device can help the second core network device complete the resource release, saving resources.

As shown in FIG. 3-3, the access network device 370 is a transceiver unit 3702 configured to receive a change indication message, wherein the change indication message causes the access network device to perform an update. The first core network device and the second core network device are used to instruct the terminal device to indicate, the first core network device and the second core network device communicate with the terminal device by using the access network device, and optionally, a change instruction message. Is a transmitting / receiving unit 370 including information about the terminal device's second key and / or the identifier of the terminal device on the second core network interface, and a processing unit 3701 configured to generate an update message. Update message Over di is the terminal device is used to instruct to perform the update, optionally, update message, the terminal device, updates the NAS type, and / or to update the key of the terminal device And a processing unit 3701 used for instructing.

  The sending / receiving unit 3702 is further configured to send the update message to the terminal device.

  The access network device may know by receiving the change indication message that the second core network device and the first core network device are well prepared for the switch. The access network device may initiate an update procedure at the terminal side by generating and sending an update message to satisfy the requirements of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, at the access network device, the processing unit 3701 is configured to generate a first message, wherein the first message is information about a root identifier of the first core network device, or a first core network device. The transceiver unit 3702 includes information about an identifier of an access network device in the network, and is configured to transmit the first message.

The access network device may inform another network element of the information required in the handover procedure by using the first message so as to be fully prepared for the handover procedure .

  Further, at the access network device, the processing unit 3701 is configured to generate an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch. , The transceiver unit 3702 is configured to send an acknowledgment message to the first core network device.

Further, at the access network device, the processing unit 3701 is configured to generate a release message, wherein the release message informs the second core network device of the connection between the terminal device and the second core network device. And the transceiver unit 3702 is configured to send a release message to the second core network device.

Based on the aforementioned release procedure, access network device, the second core network devices to obtain help to complete the resource release, to conserve resources.

As shown in FIGS. 3-4, the terminal device is a transmitting / receiving unit 3602 configured to receive an update message, wherein the update message informs the terminal device of the NAS type and / or A transmit / receive unit 3602 used to instruct to update the key of the device and a processing unit 3601 configured to update the NAS type and / or update the key of the terminal device , where the NAS Updating the type includes updating the NAS type used to communicate with the second core network device to the NAS type used to communicate with the first core network device , the terminal device Updating the key is used to communicate with the second core network device. First key includes updating the second key used to communicate with the first core network device, the first core network device and a second core network device, the same access network The device communicates with the terminal device by using the device.

The terminal device may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message to satisfy a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, at the terminal device, the processing unit is configured to generate a capability message, wherein the capability message indicates that the terminal device supports that the terminal device establishes a connection with the first core network device. Used for indicating, the transceiver unit is configured to transmit a capability message.

The terminal device informs another network element that the terminal device may support communication with the first core network device by using a capability message to fully prepare for the switch.

  [Second embodiment]

  Embodiments of the present invention provide a handover method. The method is applied to the communication system shown in FIG. The communication system includes a terminal device, an access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device. It can be seen that the second embodiment is basically the same as the first embodiment. The differences are as follows. In the first embodiment, the second core network device needs to switch a connection between the terminal device and the second core network device to a connection between the terminal device and the first core network device. However, in the second embodiment, the access network device determines that switching is required.

Based on the handover procedure is initiated by the access network device, a connection between the terminal device and a second core network device without switching the access network device, between the terminal device and the first core network devices The connection can be switched, thereby efficiently fulfilling network communication requirements.

  For simplicity of description, the same reference numbers are used for the same parts in FIGS. Therefore, details will not be described again. The different parts, such as steps 421, 422, 423 and 424, are described in detail. It can be understood that the related description of FIG. 3 can be used to describe the technical solution of FIG.

  As shown in FIG. 4, the method includes the following steps.

311. The terminal device establishes a connection with the second core network device by using the access network device.

  312. An access network device sends a first message to a second core network device, where the first message includes information about a root identifier of the first core network device or access in the first core network. Contains information about the identifier of the network device.

421. The access network device determines that a connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. Further, the access network device may initiate the switch based on conditions of the access network or a state of the second core network device. For example, the access network device infers that it can no longer accept services based on the load status of the second core network device. Instead, the access network device receives the message of the second core network device and is informed that a switch is needed, in which case the access network device is active when the switch is needed decide. It can be appreciated that the access network device may instead receive a message sent by another network element to trigger the switch.

422. The access network device sends a change message to the second core network device, wherein the change message indicates that the connection between the terminal device and the second core network device is different from the terminal device and the first core network device. It is used to notify the second core network device that it needs to be switched to a connection between. Optionally, the change message includes information about an identifier of the terminal device on the second core network interface. The identifier of the terminal device on the second core network interface is an identifier used by the access network device to identify the terminal device on the interface that communicates with the second core network device.

  Optionally, the change message may include information about a root identifier of the first core network device and / or information about an identifier of an access network device in the first core network. It can be appreciated that two types of information are used by the second core network device. If the second core network device learns the information or part of the information in another way, it is unnecessary to send the known information by using step 312 or step 422. One or both of the information about the root identifier of the first core network device and the identifier of the access network device in the first core network may be sent by using the first message in step 312. Can be understood. In this case, the change message in step 422 may not include the information sent by using the first message. Alternatively, one or both of the information about the root identifier of the first core network device and the information about the identifier of the access network device in the first core network may be sent by using a change message in step 422. In this case, the first message in step 312 may not include the information that needs to be sent by using the change message, or even step 312 may be omitted.

  423. The second core network device generates a change acknowledgment message, wherein the change acknowledgment message indicates that the connection between the terminal device and the second core network device is different from the terminal device and the first core network device. Is used to notify the first core network device that it needs to be switched to a connection between the first core network device. Optionally, the change acknowledgment message is a terminal device's first key, information about an identifier of an access network device in a first core network, and information about an identifier of the terminal device on a second core network interface. , And one or a combination thereof. The second core network device receives the change message, and the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. Knowing that, prepare communication resources accordingly. The second core network device sends corresponding information so as to allow the first core network device to connect to the terminal device without any problem. The first key of the terminal device, the information about the identifier of the access network device in the first core network, and the information about the identifier of the terminal device on the second core network interface are similar to those of the solution in FIG. Or matches. Details will not be described again.

  424. The second core network device sends a change acknowledgment message to the first core network device.

  Optionally, the second core network device may discover the first core network device based on information about a root identifier of the first core network device.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct the access network device to instruct the terminal device to perform the update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is the first key Obtained based on

  327. The first core network device sends a change indication message to the access network device.

328. The access network device generates an update message, where the update message is used to instruct the terminal device to update the NAS type and / or update the terminal device 's key. Updated key of the terminal device, based on a local key that is stored on the terminal device, is obtained.

329. The access network device notifies the update message to the terminal device, wherein the update message is used to instruct the terminal device to perform the update, and optionally, the update message Used to update the NAS type and / or to update the terminal device key.

  341. The terminal device updates the local key and / or changes the non-access layer NAS type based on the update message.

  331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

332. The first core network device sends a release message to a second core network device, wherein the release message communicates to the second core network device between the terminal device and the second core network device. Used to indicate that the connection should be released.

The method may further comprise, as an alternative to steps 331 and 332, step 331 ′: the access network device sends a release message to the second core network device, wherein the release message is To release the connection between the terminal device and the second core network device.

Further, the second core network device releases the connection between the terminal device and the second core network device (not shown).

Based on the handover procedure is initiated by the access network device, a connection between the terminal device and a second core network device without switching the access network device, a connection between the terminal device and the first core network device , Thereby efficiently fulfilling network communication requirements.

  In the flowchart of FIG. 4, the dashed lines indicate that the steps are optional. Specifically, one of steps 311, 312, 313 and 313 'or a combination thereof may be omitted, and one of steps 331, 332 and 331' or a combination thereof may be omitted. .

  The following different methods can be obtained for the various network elements of FIG. The following method is consistent with the method of FIG. 4, and the same parts will not be described again in detail. The steps of the method and the associated description in FIGS. 3 and 4 may provide a reference to the following method and have similar advantages as the following method. Details will not be described again for brevity. In the following method, it can be understood that the first core network device and the second core network device communicate with the terminal device by using the same access network device.

The handover method is used by a second core network device, wherein the second core network device receives a change message, the change message comprising a connection between the terminal device and the second core network device. Is used to notify the second core network device that it needs to be switched to a connection between the terminal device and the first core network device. Optionally, change message contains information about the identifier of the terminal device on the second core network interface, the identifier of the terminal device on the second core network interface, the access network device is a second core network This is an identifier used to identify a terminal device on an interface that communicates with the device.

  423. The second core network device generates a change acknowledgment message, wherein the change acknowledgment message indicates that the connection between the terminal device and the second core network device is different from the terminal device and the first core network device. Used to notify the first core network device that it may need to be switched to a connection between the first core network device. Optionally, the change acknowledgment message is a terminal device's first key, information about an identifier of an access network device in a first core network, and information about an identifier of the terminal device on a second core network interface. , And one or a combination thereof.

  424. The second core network device sends a change acknowledgment message to the first core network device.

  The second core network device sends a change message and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method may further comprise the following steps: 311. The terminal device establishes a connection with the second core network device.

  Further, the handover method further comprises the step of the second core network device receiving the first message, wherein the first message includes information about the root identifier of the first core network device, or the first message. Comprising information about an identifier of an access network device in the core network.

The second core network device may know the information needed in the handover procedure by using the first message so as to be fully prepared for the handover procedure .

Further, the handover method further comprises the step of the second core network device receiving a release message, wherein the release message informs the second core network device of the connection between the terminal device and the second core network device. That are used to indicate that the

Further, the handover method further comprises the second core network device releasing the connection between the terminal device and the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

A handover method is used by a first core network device , wherein the first core network device receives a change acknowledgment message, wherein the change acknowledgment message is transmitted between the terminal device and the second core network device. Comprising a step used to notify the first core network device that the connection between the terminal device and the first core network device needs to be switched to a connection between the terminal device and the first core network device. Optionally, the change acknowledgment message is a terminal device's first key, information about an identifier of an access network device in a first core network, and information about an identifier of the terminal device on a second core network interface. , And one or a combination thereof.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct an access network device to instruct a terminal device to perform an update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device identifier on the second core network interface, wherein the second key is based on the first key. Is obtained.

  327. The first core network device sends a change indication message to the access network device.

  The first core network device may know that the first core network device needs to connect with the terminal device by receiving the change acknowledgment message, and the first core network device may send a request for the network. By using the change indication message to satisfy, another network element may be notified that the first core network device and the second core network device are fully prepared for the switch. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the first core network device receiving an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch. Provided with a stage.

332. The first core network device sends a release message to a second core network device, wherein the release message establishes a connection between the terminal device and the second core network device to the second core network device. Used to indicate release.

  Based on the release procedure described above, the first core network device can help the second core network device complete the resource release, saving resources.

  A handover method is used by an access network device and comprises the following steps.

  421. The access network device determines that the connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device.

422. The access network device sends a change message to the second core network device, wherein the change message indicates that the connection between the terminal device and the second core network device is between the terminal device and the first core network device. Is used to notify the second core network device that it needs to be switched to a connection between. Change message includes information about the identifier of the terminal device on the second core network interface, the identifier of the terminal device on the second core network interface, the access network device can communicate with the second core network device This is an identifier used to identify a terminal device on the interface.

  The access network device determines that a switch is needed, sends a change message, and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the access network device transmitting a first message, wherein the first message includes information about a root identifier of the first core network device or access in the first core network. Comprising information about the identifier of the network device.

The access network device may inform another network element of the information needed in the handover procedure by using the first message so as to be fully prepared for the handover procedure .

  Further, the handover method further comprises the step of the access network device receiving a change indication message, wherein the change indication message is used to instruct the access network device to instruct the terminal device to perform the update, It has a stage. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface.

328. The access network device generates an update message, wherein the update message is used to instruct the terminal device to perform the update, and optionally, the update message indicates to the terminal device the NAS type. Used to update and / or to update the key of the terminal device . Updated key of the terminal device is obtained based on the local key that is stored on the terminal device.

329. The access network device notifies the terminal device of the update message.

  The access network device may know by receiving the change indication message that the second core network device and the first core network device are well prepared for the switch. The access network device may initiate an update procedure at the terminal side by generating and sending an update message to satisfy the requirements of the network.

  Further, the handover method further includes the following steps.

  331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

  Further, the handover method further includes the following steps.

331 '. The access network device sends a release message to the second core network device, wherein the release message causes the second core network device to release the connection between the terminal device and the second core network device. Used to indicate.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

The handover method is used by the terminal device, wherein the terminal device receives the update message, wherein the update message is used to instruct the terminal device to perform the update, and optionally, the update message is the terminal device, updates to update the NAS type, and / or used to instruct to update the key of the terminal device, in which the steps, the terminal device updates the NAS type, and / or the key of the terminal device And a step of performing

Updating the NAS type includes updating the NAS type used to communicate with the second core network device to the NAS type used to communicate with the first core network device , Updating the device key updates the first key used to communicate with the second core network device to a second key used to communicate with the first core network device. Including stages.

The terminal device may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message to satisfy a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Embodiments of the present invention provide a communication system. The communication system includes a terminal device, an access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same access network device. The system may use the handover method shown in FIG. Further, the first core network device and the second core network device may use different core network technologies. See the description in FIG.

The following device may relate to the steps of the method described in FIG. Accordingly, the method steps and the associated description in FIGS. 3 and 4 may provide reference to, and have similar advantages to, the following devices. Details will not be described again for brevity. In the following embodiments , it can be understood that the first core network device and the second core network device communicate with the terminal device by using the same access network device.

As shown in FIG. 4A, the second core network device 490 is a transmitting / receiving unit 4902 configured to receive a change message, wherein the change message is transmitted to the terminal device and the second core network device. Used to notify the second core network device that the connection between the terminal device and the first core network device needs to be switched to the connection between the terminal device and the first core network device. message includes information on the identifier of the terminal device on the second core network interface, the identifier of the terminal device on the second core network interface, interface access network device can communicate with the second core network device Used to identify the terminal device on It is an identifier, and transmitting and receiving unit 4902, a configured processing unit 4901 to generate a modified acknowledgment message, change acknowledgment message, the connection between the terminal device and a second core network device, The first acknowledgment message is used to notify the first core network device that it needs to switch to a connection between the terminal device and the first core network device, and optionally, the change acknowledgment message One of the three items, the information about the identifier of the access network device in the first core network, and the information about the identifier of the terminal device on the second core network interface, or a combination thereof. Including the processing unit 4901 Including.

  The transmitting / receiving unit 4902 is further configured to send a change acknowledgment message to the first core network device.

  The second core network device sends a change message and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, in the second core network device, the terminal device establishes a connection with the second core network device.

  Further, at the second core network device, the transmitting / receiving unit is configured to receive the first message, wherein the first message is information about a root identifier of the first core network device, or the first message. Information about the identifier of the access network device in the core network of the network.

The second core network device may know the information needed in the handover procedure by using the first message so as to be fully prepared for the handover procedure .

Further, at the second core network device, the transceiver unit is configured to receive a release message, wherein the release message is transmitted to the second core network device between the terminal device and the second core network device. Used to indicate that the connection should be released.

Further, at the second core network device, the processing unit is configured to release a connection between the terminal device and the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

  As shown in FIG. 4-2, the first core network device 480 is a transceiver unit 4802 configured to receive a change acknowledgment message, wherein the change acknowledgment message is Is used to notify the first core network device that the connection between the first core network device and the connection between the terminal device and the first core network device needs to be switched to a connection between the terminal device and the first core network device. In particular, the change acknowledgment message includes three information, such as a first key of the terminal device, information about an identifier of the access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. Contains one or a combination of the two items A transmitting / receiving unit 4802 and a processing unit 4801 configured to generate a change indication message, wherein the change indication message is used to instruct an access network device to instruct a terminal device to perform an update; Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is the first key And a processing unit 4801 obtained based on the information.

  The transmitting / receiving unit 4802 is further configured to send a change indication message to the access network device.

  The first core network device may know that the first core network device needs to connect with the terminal device by receiving the change acknowledgment message, and the first core network device may perform the change indication message. By using, the first core network device and the second core network device can be notified to another network element that they are well prepared for the switch to satisfy the demands of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

Further, at the first core network device, the transmitting / receiving unit receives an acknowledgment message used to indicate that the access network device and the terminal device have completed the switch, and sends the terminal device to the second core network device. A release message used to instruct to release the connection between the second core network device and the second core network device.

  Based on the release procedure described above, the first core network device can help the second core network device complete the resource release, saving resources.

As shown in FIG. 4-3, the access network device 470 switches the connection between the terminal device and the second core network device to the connection between the terminal device and the first core network device. A processing unit 4701 configured to determine that the change message needs to be sent to the second core network device, and a transmit / receive unit 4702 configured to send the change message to the second core network device, the change message comprising: A transmitting / receiving unit 4702 used to notify the second core network device that the connection between the network device needs to be switched to the connection between the terminal device and the first core network device; including. Optionally, change message contains information about the identifier of the terminal device on the second core network interface, the identifier of the terminal device on the second core network interface, the access network device is a second core network This is an identifier used to identify a terminal device on an interface that communicates with the device.

  The access network device determines that a switch is needed, sends a change message, and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, at the access network device, the transceiver unit 4702 is configured to transmit a first message, wherein the first message is information about a root identifier of the first core network device, or a first core network device. Contains information about the identifier of the access network device in the network.

The access network device may inform another network element of the information required in the handover procedure by using the first message, and prepares it sufficiently for the handover procedure.

  Further, at the access network device, the transceiver unit 4702 is configured to receive a change indication message, wherein the change indication message is for instructing the access network device to instruct the terminal device to perform an update. Used. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface.

The processing unit 4701 is configured to generate an update message, where the update message is used to instruct a terminal device to perform an update, and optionally, the update message is transmitted to the terminal device. Used to update the NAS type and / or to update the terminal device key.

  The transmitting / receiving unit 4702 is configured to notify the terminal device of the update message.

  The access network device may know by receiving the change indication message that the second core network device and the first core network device are well prepared for the switch. The access network device may initiate an update procedure at the terminal side by generating and sending an update message to satisfy the needs of the network.

  Further, at the access network device, the processing unit 4701 is configured to generate an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch. , The transceiver unit 4702 is configured to send an acknowledgment message to the first core network device.

Further, at the access network device, the processing unit 4701 is configured to generate a release message, wherein the release message is transmitted to the second core network device between the terminal device and the second core network device. Used to indicate to release the connection, the transceiver unit 4702 is configured to send a release message to the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

As shown in FIGS. 4-4, the terminal device is a transceiver unit 4602 configured to receive the update message, wherein the update message is used to instruct the terminal device to perform the update. And optionally, the update message is used to instruct the terminal device to update the NAS type and / or to update the key of the terminal device ; And / or a processing unit 4601 configured to update the key of the terminal device .

Updating the NAS type includes updating the NAS type used to communicate with the second core network device to the NAS type used to communicate with the first core network device , Updating the device key updates the first key used to communicate with the second core network device to a second key used to communicate with the first core network device. Including.

The terminal device may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message, satisfying a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  [Third Embodiment]

  Embodiments of the present invention provide a handover method. The method is applied to the communication system shown in FIG. 5, wherein the communication system comprises a terminal device, a first access network device, a second access network device, a first core network device, a second And a core network device. The first core network device and the second core network device communicate with the terminal device by using the same first access network device. Further, the first core network device and the second core network device may use different core network technologies. See the description in FIG. The first access network device may be compatible with two different core network technologies.

  It can be seen that the third embodiment is partially similar to the first embodiment. The same is in that the connection between the terminal device and the second core network device needs to be switched to the connection between the terminal device and the first core network device, the difference being that the terminal device Instead of using one access network device, the first is to establish a connection with the second core network device by using the second access network device. The second access network device does not necessarily need to connect directly to the first core network device. For the sake of brevity, the same reference numbers are used for the same or similar parts in FIGS. Therefore, details will not be described again. It can be understood that the related description in FIG. 3 can be used to describe the technical solution in FIG.

  As shown in FIG. 5, the method comprises the following steps.

  311. The terminal device establishes a connection with the second core network device by using the second access network device. The terminal device may establish a connection with the second core network device in a known manner. Typically, the terminal device establishes a connection with the second core network device by using the access network device. However, those skilled in the art will appreciate that the connection may be established in another manner. For example, the terminal device sends the message directly to the second core network device.

312. The first access network device sends a first message to a second core network device, wherein the first message includes information about a root identifier of the first core network device, or a first core network device. Contains information about the identifier of the access network device in the network. Information about the route identifier of the first core network device is used to indicate a second core network device by the first route message will be sent to the core network device. See the related description in FIG.

  313. The second core network device receives the capability message, where the capability message is used to indicate that the terminal device supports establishing a connection with the first core network device. It can be appreciated that the capability message may be sent by the terminal device to the second core network device or may be sent by the first access network device to the second core network device. For example, the capability message may be a non-access layer NAS message.

  514. The second access network device generates a handover message, wherein the handover message indicates that a connection between the terminal device and the second access network device is a connection between the terminal device and the first access network device. Used to indicate that it needs to be switched to. Further, the handover message includes information about the identifier of the terminal device on the second core network interface. The identifier of the terminal device on the second core network interface includes an identifier used to identify the terminal device on the interface with which the access network device communicates with the second core network device, for example, S1 AP UE ID Can be The second access network device initiates a handover procedure between the access network devices based on the handover message. Specifically, to determine the conditions under which the second access network device needs to initiate a handover procedure between access network devices, see the related art of inter-cell handover in the prior art.

  515. The second access network device sends a handover message to the first access network device.

The second access network device sends a handover message, instructing another network element to prepare to establish a connection with the terminal device .

  516. The first access network device generates a report message, wherein the report message indicates that the connection between the terminal device and the second access network device is a connection between the terminal device and the first access network device. Is used to notify the second core network device that it needs to be switched to the second core network device. Further, the report message includes information about the identifier of the terminal device on the second core network interface. Similar to the change message in the second embodiment, the report message may further include information about the root identifier of the first core network device, or information about the identifier of the access network device in the first core network.

517. The first access network device sends a report message to the second core network device. Steps 514 to 517 are similar to the conventional inter-cell handover procedure , in particular, the terminal device needs to be handed over from the second access network device in the second network to the first access network device. However, it can be understood that the first access network device is further connected to the first core network device and is a relatively specialized access network device.

  521. The second core network device determines that a connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. See step 321 in FIG. Details will not be described again. For example, the second core network device considers that the 5G service capability of the first access network device is insufficient and it is necessary to use the 4G service capability of the first access network device, A handover procedure between core network devices is started. Correspondingly, a handover from the second access network device to the first access network device is performed, but the network type is also changed.

523. The second core network device sends a change message to the first core network device, wherein the change message indicates that a connection between the terminal device and the second core network device is a connection between the terminal device and the first core network device. It is used to notify the first core network device that it needs to switch to a connection with the network device. Optionally, the change message has content such as a first key of the terminal device , information about an identifier of the access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof. See step 323. Details will not be described again.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct the access network device to instruct the terminal device to perform the update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is the first key Obtained based on See the solution in FIG.

  327. The first core network device sends a change indication message to the first access network device. Further, the first core network device may send a change indication message to the access network device based on the information about the identifier of the access network device in the first core network.

328. The first access network device generates an update message, wherein the update message is used to instruct the terminal device to perform an update, and optionally, the update message is transmitted to the terminal device by the NAS. Used to update the type and / or to update the key of the terminal device . Updated key of the terminal device, based on the local key that is stored on the terminal device, is obtained. Optionally, a new key is estimated from the local key by using the same estimation method as that of the first core network device.

  The access network device may know the terminal device whose key needs to be updated based on the information about the identifier of the terminal device on the second core network interface. The access network device receives and stores the second key locally such that the second key is used when communicating with the terminal device.

  529. The first access network device notifies the terminal device of the update message.

  If the first access network device has completed the inter-cell handover from the second access network device, in other words, if the first access network device has established a direct connection with the terminal device, the second access is no longer required. It may be appreciated that the first access network device may notify the terminal device of the update message directly without having to use a network device. As an alternative solution, the first access network device may use the second access network device to forward the update message (not shown), in other words, the second access network device It is only understood that the update message is forwarded without processing.

Optionally, the method further comprises the step of the first access network device transmitting a message to the second access network device (not shown), wherein the message has been switched and the terminal device has May be used to indicate to the second access network device that the connection may be released. The message may be sent before the update message or after the update message, and a similar function may instead be completed by using the information held in the update message.

  341. The terminal device updates the local key and / or changes the non-access layer NAS type based on the update message. See the solution in FIG.

  331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

332. The first core network device sends a release message to a second core network device, wherein the release message establishes a connection between the terminal device and the second core network device to the second core network device. Used to indicate release.

The method may further comprise, as an alternative to steps 331 and 332, a step 331 ′: the access network device sends a release message to the second core network device, wherein the release message is transmitted to the second core network device. Used to instruct the device to release the connection between the terminal device and the second core network device.

Further, the second core network device releases the connection between the terminal device and the second core network device (not shown).

Based on the handover procedure initiated by the second core network device, the connection between the terminal device and the second core network is established between the terminal device and the first core network device without switching the access network device. , So that network communication requirements are efficiently satisfied.

  Initially, only conventional inter-cell handover is started for the terminal device. Specifically, a handover from the second access network device to the first access network device is performed. However, in addition to accessing the second core network device, the first access network device accesses the first core network device, so that the second core network device is further based on conventional inter-cell handover. , Trigger a handover from the second core network device to the first core network device, thereby providing different qualities of service. For example, the UE originally performs the inter-cell handover only in the 5G network. Since the target base station is an e-eNB and the base station can also access the 4G network, the 5G core network device further hands over the UE to the 4G network, and the corresponding core network device is also a 4G EPC. In the early stages of establishing a 5G network, it can be seen that by using the above solution, the UE can be more quickly handed over to the 4G network due to insufficient service capabilities of 5G, It can be seen that the handover request is satisfied.

  In the flowchart of FIG. 5, the dashed lines indicate that the steps are optional. Specifically, one of steps 311, 312, 313, and 313 'or a combination thereof may be omitted, and one of steps 331, 332, and 331' or a combination thereof may be omitted. See the description in FIG.

  For the various network elements in FIG. 5, the following different methods can be obtained. The following method is consistent with the method in FIG. 5 and, for the same parts, details will not be described again. The steps of the method and the related description in FIG. 5 may provide a reference to the following method and have similar advantages as the following method. Details will not be described again for brevity. In the following method, it can be understood that the first core network device and the second core network device communicate with the terminal device by using the same first access network device.

  The handover method is used by a second core network device, wherein the second core network device receives the report message, wherein the report message indicates that a connection between the terminal device and the second access network device has been established. , Which is used to notify the second core network device that it needs to be switched to a connection between the terminal device and the first access network device. Further, the report message includes information about the identifier of the terminal device on the second core network interface.

  521. The second core network device determines that a connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device.

523. The second core network device sends a change message to the first core network device, wherein the change message indicates that a connection between the terminal device and the second core network device is a connection between the terminal device and the first core network device. It is used to notify the first core network device that it needs to switch to a connection with the network device. Optionally, the change message has content such as a first key of the terminal device , information about an identifier of the access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof.

  The second core network device determines that a switch is needed, sends a change message, and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the following steps: 311. The terminal device establishes a connection with the second core network device.

  Further, the handover method further comprises the step of the second core network device receiving the first message, wherein the first message includes information about the root identifier of the first core network device, or the first message. And / or the second core network device receives the capability message including information about an identifier of the access network device in the core network, wherein the capability message indicates that the terminal device has the first core network. Comprising a step used to indicate that the terminal device supports establishing a connection with the device.

The second core network device may know the information needed in the handover procedure by using the first message or the capability message to fully prepare for the handover procedure .

Furthermore, the handover method further comprises the step of the second core network device receiving a release message, wherein the release message informs the second core network device of the connection between the terminal device and the second core network device. That are used to indicate that the

Further, the handover method further comprises the second core network device releasing the connection between the terminal device and the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

The handover method is used by a first core network device , wherein the first core network device receives a change message, the change message comprising a connection between the terminal device and the second core network device. Is used to notify the first core network device that the connection between the terminal device and the first core network device needs to be switched. Optionally, the change message has content such as a first key of the terminal device , information about an identifier of the access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. At least one or a combination thereof.

  325. The first core network device generates a change indication message, wherein the change indication message is used to instruct an access network device to instruct a terminal device to perform an update. Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is the first key Obtained based on

  327. The first core network device sends a change indication message to the first access network device. Further, the first core network device may send a change indication message to the access network device based on the information about the identifier of the access network device in the first core network.

  The first core network device may know, by receiving the change message, that the first core network device needs to connect with the terminal device, and the first core network device may perform the change instruction message. By using, the first core network device and the second core network device can be notified to another network element that they are well prepared for the switch to satisfy the demands of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the first core network device receiving an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch. , Comprising steps.

332. The first core network device sends a release message to a second core network device, wherein the release message establishes a connection between the terminal device and the second core network device to the second core network device. Used to indicate release.

  Based on the release procedure described above, the first core network device can help the second core network device complete the resource release, saving resources.

  A handover method is used by a first access network device, wherein the first access network device receives a handover message, wherein the handover message indicates that a connection between the terminal device and the second access network device includes: Comprising a step used to indicate that a connection between the terminal device and the first access network device needs to be switched. Further, the handover message includes information about an identifier of the terminal device on the second core network interface, wherein the identifier of the terminal device on the second core network interface indicates that the access network device communicates with the second core network device. And the identifier used to identify the terminal device on the interface that performs the

  516. The first access network device generates a report message, wherein the report message indicates that the connection between the terminal device and the second access network device is a connection between the terminal device and the first access network device. Is used to notify the second core network device that it needs to be switched to the second core network device. Further, the report message includes information about the identifier of the terminal device on the second core network interface.

  517. The first access network device sends a report message to the second core network device.

  Optionally, the report message may further include information about a root identifier of the first core network device or information about an identifier of an access network device in the first core network.

  By generating a report message using the handover message, the first access network device may prepare for the switch and send the relevant information to the core network device to satisfy the needs of the network.

The handover method is used by a first access network device, wherein the access network device receives a change indication message, wherein the change indication message performs an update to the first access network device and to the terminal device. And a step used to instruct to instruct . Optionally, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface.

328. The access network device generates an update message , where the update message is used to instruct the terminal device to perform the update , and optionally, the update message updates the NAS type to the terminal device. , And / or to update the key of the terminal device .

529 . The access network device notifies the terminal device of the update message.

  The access network device may know by receiving the change indication message that the second core network device and the first core network device are sufficiently prepared for the switch. The access network device may initiate an update procedure at the terminal side by generating and sending an update message to satisfy the needs of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the access network device transmitting a first message, wherein the first message is information about a root identifier of the first core network device or an access in the first core network. Comprising information about the identifier of the network device.

By using the first message, the access network device may inform another network element of the information required in the handover procedure , and prepare sufficiently for the handover procedure.

  Further, the handover method further includes the following steps.

  331. The access network device sends an acknowledgment message to the first core network device, where the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch.

  Further, the handover method further includes the following steps.

331 '. The access network device sends a release message to the second core network device, wherein the release message causes the second core network device to release the connection between the terminal device and the second core network device. Used to indicate.

Based on the aforementioned release procedure, access network device, the second core network devices to obtain help to complete the resource release, to conserve resources.

A handover method is used by the terminal device, the terminal device receiving an update message, wherein the update message is used to instruct the terminal device to perform the update, and optionally, the update message Is used to instruct the terminal device to update the NAS type and / or to update the key of the terminal device, the steps and the terminal device updating the NAS type and / or the key of the terminal device . And updating the same.

The terminal device may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message, satisfying a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, the handover method further comprises the step of the terminal device transmitting a capability message, wherein the capability message indicates that the terminal device supports that the terminal device establishes a connection with the first core network device. , Which are used for

The terminal device informs another network element that the terminal device may support communication with the first core network device by using the capability information, and is fully prepared for the switch.

  A handover method is used by the access network device. The access network device is a second access network device, and the method includes the following steps.

  514. The access network device generates a handover message, wherein the handover message switches a connection between the terminal device and the second access network device to a connection between the terminal device and the first access network device. Used to indicate need. Further, the handover message includes information about the identifier of the terminal device on the second core network interface. The identifier of the terminal device on the second core network interface includes an identifier used to identify the terminal device on the interface with which the access network device communicates with the second core network device, for example, S1 AP UE ID It may be.

  515. An access network device sends a handover message to a first access network device.

The second access network device sends a handover message, instructing another network element to prepare to establish a connection with the terminal device .

Embodiments of the present invention provide a communication system. The communication system includes a terminal device, a first access network device, a second access network device, a first core network device, and a second core network device. The first core network device and the second core network device communicate with the terminal device by using the same first access network device. System may use a handover method shown in FIG. Further, the first core network device and the second core network device may use different core network technologies. For example, the first core network device may be a core network device using an LTE core network technology standard, and the second core network device may be a core network device using a 5G core network technology standard. For another example, the first core network device may be a core network device using the 5G core network technology standard, and the second core network device may be a core network device using the LTE core network technology standard. May be. The first access network device may be compatible with two different core network technologies.

The following device may relate to the steps of the method described in FIG. Thus, the method steps and related description in FIG. 5 may provide a reference to the following devices and have similar advantages as the following devices. Details will not be described again for brevity. In the following embodiments , it can be understood that the first core network device and the second core network device communicate with the terminal device by using the same first access network device.

  As shown in FIG. 5A, the second core network device 590 is a transceiver unit 5902 configured to receive a report message, wherein the report message comprises a terminal device and a second access network device. Is used to notify the second core network device that the connection between the second core network device and the connection between the terminal device and the first access network device needs to be switched, and the report message further comprises: A transmission / reception unit 5902, including information about an identifier of the terminal device on the second core network interface, and a connection between the terminal device and the second core network device, between the terminal device and the first core network device. Configured to determine that the connection needs to be switched to And a processing unit 5901 to be.

The transmitting / receiving unit 5902 is further configured to send a change message to the first core network device, wherein the change message is transmitted between the terminal device and the second core network device by the terminal device and the first core network device. Is used to notify the first core network device that the connection to the core network device needs to be switched. Optionally, the change message includes information about the first key of the terminal device and / or the identifier of the access network device in the first core network.

  The second core network device determines that a switch is needed, sends a change message, and triggers a handover procedure to allow another network element to prepare for the switch. Thus, the requirements of the network are satisfied. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, in the second core network device, the terminal device establishes a connection with the second core network device.

  Further, at the second core network device, the transceiver unit is configured to receive the first message, the first message comprising information about a root identifier of the first core network device, or the first core network device. And / or the transmitting / receiving unit is configured to receive a capability message, the capability message indicating that the terminal device establishes a connection with the first core network device. Used to indicate that the terminal device supports it.

The second core network device knows the information needed in the handover procedure by using the first message or the capability message and prepares well for the handover procedure.

Further, at the second core network device, the transmitting / receiving unit is configured to receive a release message, the release message providing the second core network device with a connection between the terminal device and the second core network device. Used to indicate release.

Further, at the second core network device, the processing unit is configured to release a connection between the terminal device and the second core network device.

  The second core network device may complete the resource release by using the release procedure described above, saving resources.

As shown in FIG. 5-2, the first core network device 580 is a transmission / reception unit 5802 configured to receive a change message, wherein the change message comprises a terminal device and a second core network device. Used to notify the first core network device that the connection between the terminal device and the first core network device needs to be switched to a connection between the terminal device and the first core network device; The message may include at least one of contents such as a first key of the terminal device , information about an identifier of the access network device in the first core network, and information about an identifier of the terminal device on the second core network interface. Transmitter / receiver unit 58 including those combinations And a processing unit 5801 configured to generate a change indication message, wherein the change indication message is used to instruct an access network device to instruct a terminal device to perform an update, and optionally In particular, the change indication message includes information about the terminal device's second key and / or the terminal device's identifier on the second core network interface, wherein the second key is based on the first key. And a processing unit 5801 obtained.

  The transmitting / receiving unit 5802 is further configured to send a change indication message to the access network device.

  By receiving the change message, the first core network device knows that the first core network device needs to connect with the terminal device, and the first core network device uses the change instruction message. Thereby, another network element may be notified that the first core network device and the second core network device are well prepared for switching, to satisfy the demands of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

Further, at the first core network device, the transceiver unit is configured to receive an acknowledgment message, wherein the acknowledgment message is for indicating that the access network device and the terminal device have completed the switch. Used, the transceiver unit is configured to send a release message to a second core network device, wherein the release message is transmitted to the second core network device between the terminal device and the second core network device. Used to indicate that the connection should be released.

  Based on the release procedure described above, the first core network device can help the second core network device complete the resource release, saving resources.

  As shown in FIG. 5-3, an access network device 570 is provided. The access network device is a first access network device and a transceiver unit 5702 configured to receive the handover message, wherein the handover message indicates that a connection between the terminal device and the second access network device is: The handover message is used to indicate that the connection between the terminal device and the first access network device needs to be switched, and the handover message provides information about the identifier of the terminal device on the second core network interface. And the identifier of the terminal device on the second core network interface is used to identify the terminal device on the interface with which the access network device communicates with the second core network device. A transmitting and receiving unit 5702, including an identifier, and a processing unit 5701 configured to generate a report message, wherein the report message establishes a connection between the terminal device and the second access network device to the terminal device and the second access network device. The second core network interface is used to notify the second core network device that it needs to switch to a connection with the first access network device, and the report message is used to notify the terminal device identifier on the second core network interface. And a processing unit 5701 that includes information about

  The transmitting / receiving unit 5702 is further configured to send the report message to the second core network device.

  Optionally, the report message may further include information about a root identifier of the first core network device, or information about an identifier of an access network device in the first core network.

  By generating a report message using the handover message, the first access network device may prepare for the switch and send the relevant information to the core network device to satisfy the needs of the network.

The first access network device 570 is a transmitting / receiving unit 5702 configured to receive a change indication message, wherein the change message indicates that a connection between the terminal device and the second core network device is different from the terminal device and the second core network device. Used to notify the first core network device that it needs to switch to a connection with the one core network device, optionally the change indication message comprises a second key of the terminal device; And / or a processing unit 5701 configured to generate an update message, the transmission / reception unit 5702 including information about an identifier of the terminal device on the second core network interface, the update message comprising : It is used to instruct to perform the update Optionally, the update message to the terminal device, updates the NAS type, and / or used to instruct to update the key of the terminal device, and a processing unit 5701.

  The transmitting / receiving unit 5702 is further configured to notify the terminal device of the update message.

  The access network device may know by receiving the change indication message that the second core network device and the first core network device are fully prepared for the switch. The access network device may initiate an update procedure at the terminal side by generating and sending an update message to satisfy the needs of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

Further, at the access network device, the processing unit 5701 is configured to generate a first message, the first message comprising information about a root identifier of the first core network device, or an access at the first core network. Including information about the identifier of the network device, the sending / receiving unit 5702 is configured to send the first message.

The access network device may inform another network element of the information required in the handover procedure by using the first message, and prepares it sufficiently for the handover procedure.

Further, at the access network device, the processing unit 5701 is configured to generate an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch. , The sending and receiving unit 5702 is configured to send an acknowledgment message to the first core network device.

Further, at the access network device, the processing unit 5701 is configured to generate a release message, wherein the release message informs the second core network device of the connection between the terminal device and the second core network device. And the transmit / receive unit 5702 is configured to send a release message to the second core network device.

Based on the aforementioned release procedure, access network device, the second core network devices to obtain help to complete the resource release, to conserve resources.

As shown in FIGS. 5-4, the terminal device is a transceiver unit 5602 configured to receive the update message , wherein the update message is used to instruct the terminal device to perform the update. And optionally, the update message is used to instruct the terminal device to update the NAS type and / or to update the key of the terminal device ; And / or a processing unit 5601 configured to update the key of the terminal device .

The terminal device may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message, satisfying a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  Further, at the terminal device, the processing unit is configured to generate a capability message, wherein the capability message indicates that the terminal device supports that the terminal device establishes a connection with the first core network device. Used for indicating, the transceiver unit is configured to transmit a capability message.

The terminal device informs another network element that the terminal device may support communication with the first core network device by using the capability message and is fully prepared for the switch.

  As shown in FIGS. 5-5, the second access network device 550 is a processing unit 5501 configured to generate a handover message, the handover message comprising a terminal device and a second access network device. Is used to indicate that the connection between the terminal device and the first access network device needs to be switched to the connection between the terminal device and the first access network device; Wherein the identifier of the terminal device on the second core network interface is used to identify the terminal device on the interface with which the access network device communicates with the second core network device. Including, including a processing unit 5501, and configured transceiver unit 5502 to transmit a handover message to the first access network device.

The terminal device may complete the handover from the second core network device to the first core network device by completing a corresponding update operation using the update message, satisfying a request of the network. In a network, a first core network device and a second core network device communicate with a terminal device by using the same access network device.

  In the above embodiments, the core network device, the access network device, and the terminal device shown in FIGS. 3 to 5 are collectively referred to as communication devices. The processing units used in these communication devices may be performed by a processor, and the transmitting and receiving units may be performed by a transceiver. A transceiver may also include necessary components such as a transmitter, a receiver, and an antenna. The structure shown in FIG. 6 or FIG. 7 may be used for these communication devices. Details are not described for ease of explanation.

  Although not shown, it can be appreciated that the communication device may further include another device, such as an input device, an output device, and a battery. A processor may include the functionality of operating one or more software programs. The software program may be stored in a memory. The processor, and the software instructions stored in the memory, may typically be configured as operations performed by the communication device. For example, the processor can operate the connection program. The memory may be a read-only memory, a flash memory, or a magnetic storage device, such as a hard disk, a floppy disk drive, or a magnetic tape. The memory may store one or more software programs, instructions, information blocks, data, and the like.

  Optionally, in some embodiments, the memory may separately store the instructions used to perform the method performed by the communication device in the methods illustrated in FIGS. 3-5. The processor may execute the instructions stored in memory and communicate in combination with other hardware (such as a transmitter, a receiver, and an antenna) in the manner shown in FIGS. The steps performed by the device may be completed. For specific work processes and advantageous effects, see the description of the communication device in the embodiment shown in FIGS.

  The steps in the foregoing method can be performed by using hardware integrated logic in a processor or by using instructions in the form of software. The processor may be a general-purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application-specific integrated circuit (Application-Specific Integrated Circuit, ASIC), a field programmable gate array (Field Programmable Gate Array, programmable logic, FPGA logic). It may be a device, a discrete gate or transistor logic device, or a discrete hardware component. A processor may implement or execute the methods, steps, and logical block diagrams disclosed in the embodiments of the present invention. A general purpose processor may be a microprocessor, or the processor may be any conventional processor or the like. The method steps disclosed in connection with embodiments of the present invention may be implemented and implemented directly by using a hardware decoding processor, or by using a combination of hardware and software modules in a decoding processor. And can be realized. The software module may be a random access memory (Random Access Memory, RAM), a flash memory, a read-only memory (Read-Only Memory, ROM), a programmable read-only memory, an electrically erasable programmable memory, or a register. May be located on a mature storage medium. The storage medium is located in the memory, and the processor reads the instructions in the memory and completes the steps in the method described above in combination with the hardware of the processor.

  Those skilled in the art will recognize that each unit and each algorithm step may be implemented by electronic hardware or a combination of computer software and electronic hardware in combination with the examples described in the embodiments disclosed herein. You can recognize what you get. Whether the functions are performed by hardware or software depends upon the particular application of the technical solution and design constraints. Those skilled in the art will be able to perform the described functions by using different methods for each particular application.

  For the sake of brevity and brevity, the detailed operational processes of the aforementioned systems, devices, and units will be referred to the corresponding processes in the foregoing method embodiments, and details will not be described again here. One skilled in the art will understand clearly.

  It should be understood that in some embodiments provided in the present application, the disclosed systems, devices, and methods may be implemented in other manners. For example, the described apparatus embodiment is merely an example. For example, the unit division is merely a logical function division, and may be another division in an actual mounting method. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the illustrated or described mutual couplings or direct couplings or communication connections may be implemented using several interfaces. Indirect coupling or communication connections between devices or units may be implemented in electronic, mechanical, or other forms.

  Units described as separate parts may or may not be physically separated. Also, the portion represented as a unit may or may not be a physical unit, may be located at one location, or may be distributed among multiple network units. Some or all of these units may be selected based on actual requirements to achieve the objectives of the solutions of the embodiments.

  In addition, the functional units in embodiments of the present invention may be integrated into one processing unit, or each of those units may be physically alone, or two or more units may be combined into one unit It may be integrated.

If the functions are implemented in software functional units and sold or used as a separate product, the functions may be stored on a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, or a part contributing to the prior art, or a part of the technical solution may be realized in the form of a software product. The computer software product is stored on a storage medium and causes a computer device (which may be a personal computer, server, or network device, etc.) or a processor to perform all or some of the method steps described in embodiments of the present invention. Includes some instructions to instruct to execute. The above-mentioned storage medium includes any medium that can store the program code, such as a USB flash drive, a removable hard disk, a read-only memory (ROM ) , a random access memory (RAM ) , a magnetic disk, or an optical disk.

  The preceding description merely identifies embodiments of the present invention and is not intended to limit the protection scope of the present invention. Any modification or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present invention shall fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (34)

At a processing unit (3901) configured to determine that a connection between a terminal device and a second core network device needs to be switched to a connection between the terminal device and a first core network device. A processing unit, wherein the first core network device and the second core network device communicate with the terminal device by using the same access network device;
A sending / receiving unit (3902) configured to send a change message to the first core network device, wherein the change message indicates that the connection between the terminal device and the second core network device is A transmission / reception unit used to notify the first core network device that it needs to switch to the connection between a terminal device and the first core network device. Device (390). The change message may include a first key of the terminal, information about an identifier of the access network device in a first core network, and information about an identifier of the terminal device on a second core network interface. Including at least one or a combination thereof,
The second core network device according to claim 1. The transmitting / receiving unit is configured to receive a first message, wherein the first message is information about a root identifier of the first core network device, or of the access network device in the first core network. Including the information about the identifier, and / or
The transceiver unit is configured to receive a capability message, wherein the capability message is used to indicate that the terminal device supports establishing a connection with the first core network device. Can be
The second core network device according to claim 1. The transmitting / receiving unit is configured to receive a release message, the release message instructing the second core network device to release the connection between the terminal and the second core network device. Used for
The second core network device according to claim 1. The processing unit is configured to release the connection between the terminal and the second core network device;
The second core network device according to any one of claims 1 to 4.   The second core network device according to any one of claims 1 to 5, wherein the second core network device establishes a connection with the terminal device. A transceiver unit (3802) configured to receive a change message, wherein the change message indicates that a connection between a terminal device and a second core network device is between the terminal device and the first core network device. Used to notify the first core network device that it needs to be switched to a connection between the first core network device and the second core network device use the same access network device By transmitting and receiving the terminal device by transmitting and receiving unit,
A processing unit (3801) configured to generate a change indication message, wherein the change indication message is used to instruct the access network device to instruct the terminal device to perform an update, A first core network device (380) comprising: a processing unit;
The transceiver unit (3802) is further configured to send the change indication message to the access network device.
A first core network device. The change indication message includes information about a second key of the terminal device and / or an identifier of the terminal device on a second core network interface, wherein the second key is based on the first key. And / or obtained
The change message includes the first key of the terminal, information about an identifier of the access network device in a first core network, and the information about the identifier of the terminal device on the second core network interface. Including at least one of the content or a combination thereof,
The first core network device according to claim 7. The transceiver unit is configured to receive an acknowledgment message, the acknowledgment message being used to indicate that the access network device and the terminal device have completed the switch.
The transmission / reception unit is configured to send a release message to the second core network device, wherein the release message is transmitted to the second core network device between the terminal and the second core network device. Used to indicate that the connection should be released;
The first core network device according to claim 7. An access network device,
A transceiver unit (3702) configured to receive a change indication message, wherein the change indication message is used to instruct the access network device to instruct a terminal device to perform an update. A transmitting / receiving unit, wherein a first core network device and a second core network device communicate with the terminal device by using the access network device;
An access network device (370), comprising: a processing unit (3701) configured to generate an update message, wherein the update message is used to instruct the terminal device to perform an update. )
The transceiver unit (3702) is further configured to send the update message to the terminal device.
Access network device. The change indication message includes information about a second key of the terminal device and / or an identifier of the terminal device on a second core network interface.
An access network device according to claim 10. The update message is used to instruct the terminal device to update a NAS type and / or to update a key of the terminal.
An access network device according to claim 10. The processing unit 3701 is configured to generate a first message, wherein the first message is information about a root identifier of the first core network device, or of the access network device in the first core network. Contains information about the identifier,
The transmitting / receiving unit 3702 is configured to transmit the first message,
An access network device according to claim 11 or claim 12. The processing unit 3701 is configured to generate an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed a switch,
The transceiver unit 3702 is configured to send the acknowledgment message to the first core network device.
An access network device according to any one of claims 11 to 13. The processing unit 3701 is configured to generate a release message, wherein the release message instructs the second core network device to release a connection between the terminal and the second core network device. Used for
The transceiver unit 3702 is configured to send the release message to the second core network device.
An access network device according to any one of claims 11 to 14. A terminal device (360),
A transceiver unit (3602) configured to receive an update message, wherein the update message is used to instruct the terminal device to update a NAS type and / or to update a key of the terminal. , A transmitting and receiving unit,
A processing unit (3601) configured to update the NAS type and / or to update the key of the terminal.
Updating the NAS type includes updating the NAS type used to communicate with the second core network device to the NAS type used to communicate with the first core network;
Updating the key of the terminal comprises replacing a first key used to communicate with the second core network device with a second key used to communicate with the first core network. Including updating to
The first core network device and the second core network device communicate with the terminal device by using the same access network device;
Terminal device. The processing unit is configured to generate a capability message, wherein the capability message is used to indicate that the terminal device supports the terminal device establishing a connection with the first core network device. And
The transceiver unit is configured to transmit the capability message;
The terminal device according to claim 16. A second core network device determines that a connection between the terminal device and the second core network device needs to be switched to a connection between the terminal device and the first core network device. A step, wherein the first core network device and the second core network device communicate with the terminal device by using the same access network device;
The second core network device sending a change message to the first core network device, wherein the change message indicates that the connection between the terminal device and the second core network device is Using the terminal device and the first core network device to notify the first core network device that the connection needs to be switched to the connection.   The change message may include a first key of the terminal, information about an identifier of the access network device in a first core network, and information about an identifier of the terminal device on a second core network interface. 19. The method according to claim 18, comprising at least one or a combination thereof. The handover method further comprises:
Wherein the second core network device receives a first message, wherein the first message is information about a root identifier of the first core network device or in the first core network. Including the information about the identifier of the access network device, and / or
The second core network device receiving a capability message, the capability message supporting the terminal device to establish a connection with the first core network device; 20. The method according to claim 18 or 19, comprising a step used to indicate The handover method further comprises:
The second core network device receiving a release message, wherein the release message informs the second core network device of the connection between the terminal and the second core network device. 21. The method according to any one of claims 18 to 20, comprising a step used to indicate release. The handover method further comprises:
22. The method according to any one of claims 18 to 21, comprising the second core network device releasing the connection between the terminal and the second core network device.   The method according to any one of claims 18 to 22, wherein the handover method further comprises the step of the terminal device establishing a connection with the second core network device. The first core network receiving a change message, wherein the change message indicates that a connection between a terminal device and a second core network device is established between the terminal device and the first core network device. The first core network device and the second core network device are used to notify the first core network device that the connection needs to be switched to the first access network device. Communicating with the terminal device by using
Wherein the first core network device generates a change indication message, wherein the change indication message is used to instruct the access network device to instruct the terminal device to perform an update. , Stages,
Transmitting the change indication message to the access network device by the first core network device.   The change message may include a first key of the terminal, information about an identifier of the access network device in a first core network, and information about an identifier of the terminal device on a second core network interface. Comprising at least one or a combination thereof, and / or the change indication message comprises a second key of the terminal device and / or the identifier for the identifier of the terminal device on the second core network interface. 25. The method of claim 24, comprising information, wherein the second key is obtained based on the first key. The handover method further comprises:
The first core network device receiving an acknowledgment message, wherein the acknowledgment message is used to indicate that the access network device and the terminal device have completed the switch; Stages and
The first core network device sending a release message to the second core network device, wherein the release message is transmitted to the second core network device by the terminal and the second core network. Used to instruct to release said connection with the device.
The method according to claim 24 or 25. A handover method,
The access network device receiving a change indication message, wherein the change indication message is used to instruct the access network device to instruct a terminal device to perform an update, and A core network device and a second core network device communicate with the terminal device by using the access network device;
The access network device generating an update message, wherein the update message is used to instruct the terminal device to perform an update;
Transmitting the update message to the terminal device by the core network device. The change indication message includes information about a second key of the terminal device and / or an identifier of the terminal device on a second core network interface.
A method according to claim 27.   The method according to claim 27 or 28, wherein the update message is used to instruct the terminal device to update a NAS type and / or to update a key of the terminal. The handover method further comprises:
The access network device transmitting a first message to a transmission, wherein the first message includes information about a root identifier of the first core network device or the access network in a first core network. 30. The method according to any one of claims 27 to 29, comprising the step of including information about an identifier of the device. The handover method further comprises:
The access network device sending an acknowledgment message to the first core network device, wherein the acknowledgment message indicates that the access network device and the terminal device have completed a switch. 31. The method according to any one of claims 27 to 30, comprising the steps of: The handover method further comprises:
The access network device transmitting a release message to the second core network device, wherein the release message is transmitted to the second core network device by the terminal and the second core network device. 32. The method according to any one of claims 27 to 31, comprising a step used to indicate to release a connection between. A handover method,
A terminal device receiving an update message, wherein the update message is used to instruct the terminal device to update a NAS type and / or to update a key of the terminal. ,
The terminal device updating the NAS type and / or updating the key of the terminal.
Updating the NAS type includes updating the NAS type used to communicate with the second core network device to the NAS type used to communicate with the first core network;
The step of updating the terminal's key comprises replacing a first key used to communicate with the second core network device with a second key used to communicate with the first core network. Including the step of updating to
The first core network device and the second core network device communicate with the terminal device by using the same access network device;
Handover method. The handover method further comprises:
The terminal device transmitting a capability message, wherein the capability message indicates that the terminal device supports that the terminal device establishes a connection with the first core network device. 34. The method of claim 33, comprising a step used.